{"id":48247,"date":"2019-11-08T19:37:57","date_gmt":"2019-11-08T18:37:57","guid":{"rendered":"https:\/\/www.thermal-engineering.org\/o-que-e-processo-adiabatico-definicao\/"},"modified":"2020-01-28T14:03:59","modified_gmt":"2020-01-28T13:03:59","slug":"o-que-e-processo-adiabatico-definicao","status":"publish","type":"post","link":"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-processo-adiabatico-definicao\/","title":{"rendered":"O que \u00e9 processo adiab\u00e1tico &#8211; defini\u00e7\u00e3o"},"content":{"rendered":"<div class=\"su-quote su-quote-style-default\">\n<div class=\"su-quote-inner su-clearfix\">Um processo adiab\u00e1tico \u00e9 um processo termodin\u00e2mico, no qual n\u00e3o h\u00e1 transfer\u00eancia de calor para dentro ou para fora do sistema (Q = 0). O sistema pode ser considerado perfeitamente isolado. Engenharia T\u00e9rmica<\/div>\n<\/div>\n<div><\/div>\n<div><\/div>\n<div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-50 lgc-tablet-grid-50 lgc-mobile-grid-100 lgc-equal-heights  lgc-first\">\n<div class=\"inside-grid-column\">\n<h2><span>Processo Adiab\u00e1tico<\/span><\/h2>\n<p><span>Um\u00a0<\/span><strong><span>processo adiab\u00e1tico<\/span><\/strong><span>\u00a0\u00e9 um\u00a0<\/span><a title=\"Processos termodin\u00e2micos\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-processo-termodinamico-definicao\/\"><span>processo termodin\u00e2mico<\/span><\/a><span>\u00a0, no qual n\u00e3o\u00a0<\/span><strong><span>h\u00e1 transfer\u00eancia de calor para<\/span><\/strong><span>\u00a0dentro ou para fora do sistema (Q = 0).\u00a0O sistema pode ser considerado\u00a0<\/span><strong><span>perfeitamente isolado<\/span><\/strong><span>\u00a0.\u00a0Em um processo adiab\u00e1tico, a energia \u00e9 transferida apenas como trabalho.\u00a0A suposi\u00e7\u00e3o de que n\u00e3o h\u00e1 transfer\u00eancia de calor \u00e9 muito importante, pois podemos usar a aproxima\u00e7\u00e3o adiab\u00e1tica apenas em\u00a0<\/span><strong><span>processos muito r\u00e1pidos<\/span><\/strong><span>\u00a0.\u00a0Nesses processos r\u00e1pidos, n\u00e3o h\u00e1 tempo suficiente para que a transfer\u00eancia de energia como calor ocorra de ou para o sistema.<\/span><\/p>\n<p><span>Em dispositivos reais (como turbinas, bombas e compressores)\u00a0ocorrem\u00a0<\/span><strong><span>perdas<\/span><\/strong><span>\u00a0e\u00a0<strong>perdas de calor<\/strong>\u00a0no processo de combust\u00e3o, mas essas perdas s\u00e3o geralmente baixas em compara\u00e7\u00e3o com o fluxo geral de energia e podemos aproximar alguns processos termodin\u00e2micos pelo processo adiab\u00e1tico.\u00a0<\/span><\/p>\n<div class=\"su-accordion\">\n<div class=\"su-spoiler su-spoiler-style-default su-spoiler-icon-plus su-spoiler-closed\">\n<div class=\"su-spoiler-content su-clearfix\"><\/div>\n<\/div>\n<\/div>\n<div class=\"su-divider su-divider-style-dotted\"><\/div>\n<div class=\"su-spacer\"><\/div>\n<h2><span>Processo Adiab\u00e1tico e a Primeira Lei<\/span><\/h2>\n<p><span>Para um sistema fechado, podemos escrever a\u00a0\u00a0<\/span><strong><a title=\"Primeira lei em termos de entalpia dH = dQ + Vdp\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/first-law-of-thermodynamics\/first-law-in-terms-of-enthalpy-dh-dq-vdp\/\"><span>primeira lei da termodin\u00e2mica em termos de entalpia<\/span><\/a><\/strong><span>\u00a0:<\/span><\/p>\n<p><strong><span>dH = dQ + Vdp<\/span><\/strong><\/p>\n<p><span>Nesta equa\u00e7\u00e3o, o termo\u00a0<\/span><strong><span>Vdp<\/span><\/strong><span>\u00a0\u00e9 um\u00a0<\/span><strong><a title=\"Trabalho p\u0394V - Trabalho de Fronteira e Trabalho V\u0394p\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/first-law-of-thermodynamics\/p%ce%b4v-work-boundary-work-and-v%ce%b4p-work\/\"><span>trabalho de processo de fluxo<\/span><\/a><span>\u00a0.\u00a0<\/span><\/strong><span>Este trabalho, Vdp, \u00e9 usado para sistemas de fluxo aberto, como uma turbina ou uma bomba na qual existe um &#8220;dp&#8221;, ou seja, mudan\u00e7a de press\u00e3o.\u00a0Como pode ser visto, essa forma de lei\u00a0<\/span><strong><span>simplifica a descri\u00e7\u00e3o da transfer\u00eancia de energia<\/span><\/strong><span>\u00a0.\u00a0No processo adiab\u00e1tico, a\u00a0<\/span><strong><span>mudan\u00e7a de entalpia<\/span><\/strong><span>\u00a0\u00e9 igual ao\u00a0<\/span><strong><span>trabalho do processo de fluxo<\/span><\/strong><span>\u00a0realizado no ou pelo sistema:<\/span><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-50 lgc-tablet-grid-50 lgc-mobile-grid-100 lgc-equal-heights  lgc-last\">\n<div class=\"inside-grid-column\">\n<figure id=\"attachment_17354\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-17354\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Adiabatic-Process-main-characteristics1.png\"><img loading=\"lazy\" class=\"size-full wp-image-17354 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Adiabatic-Process-main-characteristics1.png\" alt=\"Principais caracter\u00edsticas do processo adiab\u00e1tico\" width=\"380\" height=\"564\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Adiabatic-Process-main-characteristics1.png\" \/><\/a><figcaption id=\"caption-attachment-17354\" class=\"wp-caption-text\"><span>Principais caracter\u00edsticas do processo adiab\u00e1tico<\/span><\/figcaption><\/figure>\n<p><span>Veja tamb\u00e9m:\u00a0<\/span><a title=\"Primeira Lei da Termodin\u00e2mica\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-a-primeira-lei-da-termodinamica-definicao\/\"><span>Primeira lei da termodin\u00e2mica<\/span><\/a><\/p>\n<p><span>Veja tamb\u00e9m:\u00a0<\/span><a title=\"Lei do g\u00e1s ideal\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/ideal-gas-law\/\"><span>Lei do g\u00e1s ideal<\/span><\/a><\/p>\n<p><span>Veja tamb\u00e9m:\u00a0<\/span><a title=\"O que \u00e9 entalpia\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/what-is-energy-physics\/what-is-enthalpy\/\"><span>O que \u00e9 entalpia<\/span><\/a><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\"><strong><span>Processo adiab\u00e1tico (dQ = 0):<\/span><\/strong><strong><span>dH = Vdp \u2192 W = H\u00a0<\/span><\/strong><strong><sub><span>2<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>1<\/span><\/sub><\/strong><strong><span>\u00a0\u00a0\u00a0\u00a0\u00a0\u2192 H\u00a0<\/span><\/strong><strong><sub><span>2<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>1<\/span><\/sub><\/strong><strong><span>\u00a0=\u00a0<\/span><em><span>C\u00a0<\/span><\/em><\/strong><strong><em><sub><span>P<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0(T\u00a0<\/span><\/em><\/strong><strong><em><sub><span>2<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0&#8211; T\u00a0<\/span><\/em><\/strong><strong><em><sub><span>1<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0) \u00a0\u00a0\u00a0<\/span><\/em><\/strong><em><span>\u00a0(para um\u00a0\u00a0<\/span><a title=\"O que \u00e9 o g\u00e1s ideal\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/ideal-gas-law\/what-is-ideal-gas\/\"><span>g\u00e1s ideal<\/span><\/a><span>\u00a0)<\/span><\/em><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Expans\u00e3o Adiab\u00e1tica &#8211; Compress\u00e3o Adiab\u00e1tica<\/span><\/h2>\n<p><span>Veja tamb\u00e9m:\u00a0<\/span><a title=\"O que \u00e9 o g\u00e1s ideal\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/ideal-gas-law\/what-is-ideal-gas\/\"><span>O que \u00e9 um g\u00e1s ideal<\/span><\/a><\/p>\n<p><span>Num\u00a0<\/span><a title=\"O que \u00e9 o g\u00e1s ideal\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/ideal-gas-law\/what-is-ideal-gas\/\"><span>g\u00e1s ideal<\/span><\/a><span>\u00a0, as mol\u00e9culas n\u00e3o t\u00eam volume e n\u00e3o interagem.\u00a0De acordo com a\u00a0<\/span><a title=\"Lei do g\u00e1s ideal\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/ideal-gas-law\/\"><span>lei ideal dos gases<\/span><\/a><span>\u00a0, a\u00a0<\/span><a title=\"O que \u00e9 press\u00e3o - F\u00edsica\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/thermodynamic-properties\/what-is-pressure-physics\/\"><span>press\u00e3o<\/span><\/a><span>\u00a0varia linearmente com a\u00a0<\/span><a title=\"O que \u00e9 temperatura - F\u00edsica\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-temperatura-fisica-definicao\/\"><span>temperatura<\/span><\/a><span>\u00a0e a quantidade e inversamente com o\u00a0<\/span><a title=\"O que \u00e9 volume - F\u00edsica\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/thermodynamic-properties\/what-is-volume-physics\/\"><span>volume<\/span><\/a><span>\u00a0.<\/span><\/p>\n<p><strong><em><span>pV = nRT<\/span><\/em><\/strong><\/p>\n<p><span>Onde:<\/span><\/p>\n<ul>\n<li><em><span>p<\/span><\/em><span>\u00a0\u00e9 a press\u00e3o absoluta do g\u00e1s<\/span><\/li>\n<li><em><span>n<\/span><\/em><span>\u00a0\u00e9 a quantidade de subst\u00e2ncia<\/span><\/li>\n<li><em><span>T<\/span><\/em><span>\u00a0\u00e9 a temperatura absoluta<\/span><\/li>\n<li><em><span>V<\/span><\/em><span>\u00a0\u00e9 o volume<\/span><\/li>\n<li><em><span>R<\/span><\/em><span>\u00a0\u00a0\u00e9 a constante de g\u00e1s ideal, ou universal, igual ao produto da constante de Boltzmann e da constante de Avogadro,<\/span><\/li>\n<\/ul>\n<p><span>Nesta equa\u00e7\u00e3o, o s\u00edmbolo R \u00e9 uma constante chamada constante\u00a0<\/span><strong><span>universal de g\u00e1s<\/span><\/strong><span>\u00a0que tem o mesmo valor para todos os gases &#8211; ou seja, R = 8,31 J \/ mol K.<\/span><\/p>\n<p><span>O\u00a0<\/span><strong><span>processo adiab\u00e1tico<\/span><\/strong><span>\u00a0\u00a0pode ser expresso com a\u00a0<\/span><strong><span>lei do g\u00e1s ideal<\/span><\/strong><span>\u00a0como:<\/span><\/p>\n<p><strong><em><span>pV\u00a0<\/span><sup><span>\u03ba<\/span><\/sup><span>\u00a0= constante<\/span><\/em><\/strong><\/p>\n<p><span>ou<\/span><\/p>\n<p><em><strong><span>p\u00a0<\/span><sub><span>1<\/span><\/sub><span>\u00a0V\u00a0<\/span><sub><span>1\u00a0<\/span><\/sub><sup><span>k<\/span><\/sup><span>\u00a0= p\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0V\u00a0<\/span><sub><span>2\u00a0<\/span><\/sub><sup><span>k<\/span><\/sup><\/strong><\/em><\/p>\n<p><span>em que\u00a0<\/span><strong><span>\u03ba = c\u00a0<\/span><sub><span>p<\/span><\/sub><span>\u00a0\/ c\u00a0<\/span><sub><span>v<\/span><\/sub><\/strong><span>\u00a0\u00e9 a propor\u00e7\u00e3o de\u00a0<a title=\"Capacidade t\u00e9rmica - Capacidade t\u00e9rmica espec\u00edfica\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/first-law-of-thermodynamics\/heat-capacity\/\"><strong>aquecimentos espec\u00edficos<\/strong><\/a>\u00a0(ou\u00a0<strong>capacidades de calor<\/strong>\u00a0) para o g\u00e1s.\u00a0Um para\u00a0<strong>press\u00e3o constante (c\u00a0<\/strong><strong><sub>p<\/sub><\/strong><strong>\u00a0)<\/strong>\u00a0e outro para\u00a0<strong>volume constante (c\u00a0<\/strong><strong><sub>v<\/sub><\/strong><strong>\u00a0)<\/strong>\u00a0.\u00a0Observe que essa raz\u00e3o\u00a0<strong>\u03ba\u00a0\u00a0<\/strong><strong>= c\u00a0<\/strong><strong><sub>p<\/sub><\/strong><strong>\u00a0\/ c\u00a0<\/strong><strong><sub>v<\/sub><\/strong>\u00a0\u00e9 um fator na determina\u00e7\u00e3o da velocidade do som em um g\u00e1s e em outros processos adiab\u00e1ticos.<\/span><\/p>\n<p><strong><span>Outra rela\u00e7\u00e3o p, V, T<\/span><\/strong><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/pVT-relation-isentropic-process.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-17281 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/pVT-relation-isentropic-process.png\" alt=\"rela\u00e7\u00e3o p, V, T - processo isentr\u00f3pico\" width=\"209\" height=\"72\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/pVT-relation-isentropic-process.png\" \/><\/a><\/p>\n<p><span>Em um\u00a0<\/span><strong><span>diagrama de pV<\/span><\/strong><span>\u00a0, o processo ocorre ao longo de uma linha (chamada\u00a0<\/span><strong><span>adiabat<\/span><\/strong><span>\u00a0) que possui a equa\u00e7\u00e3o\u00a0<\/span><strong><span>p = constante \/ V\u00a0<\/span><sup><span>\u03ba<\/span><\/sup><\/strong><span>\u00a0.\u00a0<\/span><strong><span>Para um g\u00e1s ideal e um processo politr\u00f3pico, o caso\u00a0<\/span><i><span>n = \u03ba\u00a0<\/span><\/i><\/strong><span><strong>corresponde a um processo adiab\u00e1tico.<\/strong><\/span><i>\u00a0\u00a0<\/i><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Exemplo de expans\u00e3o adiab\u00e1tica<\/span><\/h2>\n<figure id=\"attachment_17362\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-17362\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/P-V-diagram-adiabatic-process.png\"><img loading=\"lazy\" class=\"size-medium wp-image-17362 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/P-V-diagram-adiabatic-process-300x251.png\" alt=\"Diagrama PV - processo adiab\u00e1tico\" width=\"300\" height=\"251\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/P-V-diagram-adiabatic-process-300x251.png\" \/><\/a><figcaption id=\"caption-attachment-17362\" class=\"wp-caption-text\"><span>Assuma uma expans\u00e3o adiab\u00e1tica de h\u00e9lio (3 \u2192 4) em uma turbina a g\u00e1s (ciclo de Brayton).<\/span><\/figcaption><\/figure>\n<p><span>Assuma uma\u00a0<\/span><strong><span>expans\u00e3o adiab\u00e1tica<\/span><\/strong><span>\u00a0de h\u00e9lio (\u00a0<\/span><strong><span>3 \u2192 4<\/span><\/strong><span>\u00a0) em uma\u00a0<\/span><strong><span>turbina a g\u00e1s<\/span><\/strong><span>\u00a0.\u00a0Como o h\u00e9lio se comporta quase como um\u00a0<\/span><a title=\"O que \u00e9 o g\u00e1s ideal\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/ideal-gas-law\/what-is-ideal-gas\/\"><span>g\u00e1s ideal<\/span><\/a><span>\u00a0, use a\u00a0<\/span><a title=\"Lei do g\u00e1s ideal\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/ideal-gas-law\/\"><span>lei do g\u00e1s ideal<\/span><\/a><span>\u00a0para calcular a\u00a0<\/span><strong><span>temperatura<\/span><\/strong><span>\u00a0de\u00a0<strong>sa\u00edda<\/strong>\u00a0do g\u00e1s (\u00a0<\/span><strong><span>T\u00a0<\/span><sub><span>4, real<\/span><\/sub><\/strong><span>\u00a0).\u00a0Nessas turbinas, o est\u00e1gio de alta press\u00e3o recebe g\u00e1s (ponto 3 na figura; p\u00a0<\/span><sub><span>3<\/span><\/sub><span>\u00a0=\u00a0<\/span><strong><span>6,7 MPa<\/span><\/strong><span>\u00a0;\u00a0<\/span><strong><span>T\u00a0<\/span><sub><span>3<\/span><\/sub><span>\u00a0= 1190 K<\/span><\/strong><span>\u00a0(917 \u00b0 C)) de um trocador de calor e o esgota em outro trocador de calor, onde a press\u00e3o de sa\u00edda \u00e9 p\u00a0<\/span><sub><span>4<\/span><\/sub><span>\u00a0=\u00a0<\/span><strong><span>2,78 MPa<\/span><\/strong><span>\u00a0(ponto 4)\u00a0<\/span><strong><span>.<\/span><\/strong><\/p>\n<p><strong><span>Solu\u00e7\u00e3o:<\/span><\/strong><\/p>\n<p><span>A temperatura de sa\u00edda do g\u00e1s, T4\u00a0<\/span><sub><span>, real<\/span><\/sub><span>\u00a0, pode ser calculada usando a rela\u00e7\u00e3o\u00a0<\/span><strong><span>p, V, T<\/span><\/strong><span>\u00a0para um processo adiab\u00e1tico.\u00a0Observe que, \u00e9 a mesma rela\u00e7\u00e3o do\u00a0<\/span><a title=\"Processo isentr\u00f3pico\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-processo-isentropico-definicao\/\"><span>processo isentr\u00f3pico<\/span><\/a><span>\u00a0, portanto, os resultados devem ser id\u00eanticos.\u00a0Nesse caso, calculamos a expans\u00e3o para diferentes turbinas a g\u00e1s (menos eficientes), como no caso da\u00a0<\/span><strong><span>expans\u00e3o isentr\u00f3pica na turbina a g\u00e1s.<\/span><\/strong><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/pVT-relation-isentropic-process.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-17281 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/pVT-relation-isentropic-process.png\" alt=\"rela\u00e7\u00e3o p, V, T - processo isentr\u00f3pico\" width=\"209\" height=\"72\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/pVT-relation-isentropic-process.png\" \/><\/a><\/p>\n<p><span>Nesta equa\u00e7\u00e3o, o fator para o h\u00e9lio \u00e9 igual a\u00a0<\/span><strong><span>\u03ba\u00a0<\/span><\/strong><strong><span>= c\u00a0<\/span><sub><span>p<\/span><\/sub><span>\u00a0\/ c\u00a0<\/span><sub><span>v<\/span><\/sub><span>\u00a0= 1,66<\/span><\/strong><span>\u00a0.\u00a0A partir da equa\u00e7\u00e3o anterior, segue que a temperatura de sa\u00edda do g\u00e1s,\u00a0<\/span><strong><span>T4\u00a0<\/span><sub><span>, real<\/span><\/sub><\/strong><span>\u00a0, \u00e9:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/adiabatic-process-example.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-17307 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/adiabatic-process-example.png\" alt=\"processo adiab\u00e1tico - exemplo\" width=\"518\" height=\"80\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/adiabatic-process-example.png\" \/><\/a><\/p>\n<p><span>Veja tamb\u00e9m:\u00a0\u00a0<\/span><a title=\"Rela\u00e7\u00e3o de Mayer - f\u00f3rmula de Mayer\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/ideal-gas-law\/mayers-relation-mayers-formula\/\"><strong><span>Rela\u00e7\u00e3o de Mayer<\/span><\/strong><\/a><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Processo adiab\u00e1tico em turbina a g\u00e1s<\/span><\/h2>\n<figure id=\"attachment_16843\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-16843\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/first-law-example-brayton-cycle.png\"><img loading=\"lazy\" class=\"size-medium wp-image-16843 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/first-law-example-brayton-cycle-300x244.png\" alt=\"primeira lei - exemplo - ciclo de brayton\" width=\"300\" height=\"244\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/first-law-example-brayton-cycle-300x244.png\" \/><\/a><figcaption id=\"caption-attachment-16843\" class=\"wp-caption-text\"><span>O ciclo ideal de Brayton consiste em quatro processos termodin\u00e2micos.\u00a0Dois processos isentr\u00f3picos e dois processos isob\u00e1ricos.<\/span><\/figcaption><\/figure>\n<p><span>Vamos assumir o\u00a0\u00a0<\/span><strong><span>ciclo de Brayton<\/span><\/strong><span>\u00a0\u00a0que descreve o funcionamento de um\u00a0\u00a0<strong>motor de calor com\u00a0<\/strong><\/span><strong><span>press\u00e3o constante<\/span><\/strong>\u00a0<span>\u00a0.\u00a0<strong>Os modernos<\/strong>\u00a0\u00a0motores de\u00a0<strong>turbina a g\u00e1s<\/strong>\u00a0e os motores a\u00a0\u00a0<strong>jato de respira\u00e7\u00e3o<\/strong>\u00a0\u00a0tamb\u00e9m seguem o ciclo de Brayton.<\/span><\/p>\n<p><span>O ciclo de Brayton consiste em quatro processos termodin\u00e2micos.\u00a0Dois processos adiab\u00e1ticos e dois processos isob\u00e1ricos.<\/span><\/p>\n<ol>\n<li><strong><span>compress\u00e3o adiab\u00e1tica<\/span><\/strong><span>\u00a0\u00a0&#8211; o ar ambiente \u00e9 aspirado para o compressor, onde \u00e9 pressurizado (1 \u2192 2).\u00a0O trabalho necess\u00e1rio para o compressor \u00e9 dado por\u00a0\u00a0<\/span><strong><span>W\u00a0<\/span><sub><span>C<\/span><\/sub><span>\u00a0\u00a0= H\u00a0<\/span><sub><span>2<\/span><\/sub><span>\u00a0\u00a0&#8211; H\u00a0<\/span><sub><span>1<\/span><\/sub><span>\u00a0.<\/span><\/strong><\/li>\n<li><strong><span>adi\u00e7\u00e3o de calor isob\u00e1rico<\/span><\/strong><span>\u00a0\u00a0&#8211; o ar comprimido passa por uma c\u00e2mara de combust\u00e3o, onde o combust\u00edvel \u00e9 queimado e o ar ou outro meio \u00e9 aquecido (2 \u2192 3).\u00a0\u00c9 um processo de press\u00e3o constante, j\u00e1 que a c\u00e2mara est\u00e1 aberta para entrar e sair.\u00a0O calor l\u00edquido adicionado \u00e9 dado por\u00a0\u00a0<\/span><strong><span>Q\u00a0<\/span><sub><span>add<\/span><\/sub><span>\u00a0\u00a0= H\u00a0<\/span><sub><span>3\u00a0<\/span><\/sub><span>\u00a0&#8211; H\u00a0<\/span><sub><span>2<\/span><\/sub><\/strong><\/li>\n<li><strong><span>expans\u00e3o adiab\u00e1tica<\/span><\/strong><span>\u00a0\u00a0&#8211; o ar aquecido e pressurizado se expande na turbina, gasta sua energia.\u00a0O trabalho realizado pela turbina \u00e9 dado por\u00a0\u00a0<\/span><strong><span>W\u00a0<\/span><sub><span>T<\/span><\/sub><span>\u00a0\u00a0= H\u00a0<\/span><sub><span>4<\/span><\/sub><span>\u00a0\u00a0&#8211; H\u00a0<\/span><sub><span>3<\/span><\/sub><\/strong><\/li>\n<li><strong><span>rejei\u00e7\u00e3o de calor isob\u00e1rica<\/span><\/strong><span>\u00a0\u00a0&#8211; o calor residual deve ser rejeitado para fechar o ciclo.\u00a0O calor l\u00edquido rejeitado \u00e9 dado por\u00a0\u00a0<\/span><strong><span>Q\u00a0<\/span><sub><span>re<\/span><\/sub><span>\u00a0\u00a0= H\u00a0<\/span><sub><span>4\u00a0<\/span><\/sub><span>\u00a0&#8211; H\u00a0<\/span><sub><span>1<\/span><\/sub><\/strong><\/li>\n<\/ol>\n<p><span>Como pode ser visto, podemos descrever e calcular (por exemplo,\u00a0<\/span><a title=\"Efici\u00eancia t\u00e9rmica\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-eficiencia-termica-definicao\/\"><span>efici\u00eancia t\u00e9rmica<\/span><\/a><span>\u00a0) esses ciclos (da mesma forma para o\u00a0\u00a0<\/span><strong><span>ciclo de Rankine<\/span><\/strong><span>\u00a0) usando\u00a0\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/what-is-energy-physics\/what-is-enthalpy\/\"><span>entalpias<\/span><\/a><span>\u00a0.<\/span><\/p>\n<p><span>Veja tamb\u00e9m:\u00a0<\/span><a title=\"Efici\u00eancia t\u00e9rmica do ciclo de Brayton\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/thermal-efficiency\/thermal-efficiency-of-brayton-cycle\/\"><span>Efici\u00eancia t\u00e9rmica do ciclo de Brayton<\/span><\/a><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-60 lgc-tablet-grid-60 lgc-mobile-grid-100 lgc-equal-heights  lgc-first\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Efici\u00eancia isentr\u00f3pica &#8211; turbina, compressor, bocal<\/span><\/h2>\n<p><span>Nos cap\u00edtulos anteriores assumiu-se que a expans\u00e3o do g\u00e1s \u00e9\u00a0<\/span><strong><span>isentr\u00f3pica<\/span><\/strong><span>\u00a0e, portanto, utilizou-se\u00a0<\/span><strong><span>o t\u00a0<\/span><sub><span>4, \u00e9<\/span><\/sub><\/strong><span>\u00a0\u00a0como a temperatura de sa\u00edda do g\u00e1s.\u00a0Essas premissas s\u00e3o aplic\u00e1veis \u200b\u200bapenas aos ciclos ideais.<\/span><\/p>\n<p><span>A maioria\u00a0<\/span><strong><span>dos dispositivos de fluxo constante<\/span><\/strong><span>\u00a0(turbinas, compressores, bicos) opera em\u00a0<\/span><strong><span>condi\u00e7\u00f5es adiab\u00e1ticas<\/span><\/strong><span>\u00a0, mas n\u00e3o s\u00e3o verdadeiramente isentr\u00f3picos, mas s\u00e3o idealizados como isentr\u00f3picos para fins de c\u00e1lculo.\u00a0Definimos os par\u00e2metros\u00a0<\/span><strong><em><span>\u03b7\u00a0<\/span><\/em><\/strong><strong><em><sub><span>T<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0,\u00a0<\/span><\/em><\/strong>\u00a0<strong><em><span>\u03b7\u00a0<\/span><\/em><\/strong><strong><em><sub><span>C<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0, \u03b7\u00a0<\/span><\/em><\/strong><strong><em><sub><span>N<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0,<\/span><\/em><\/strong><span>\u00a0como uma\u00a0<\/span><strong><span>raz\u00e3o<\/span><\/strong><span>\u00a0entre\u00a0<\/span><strong><span>o trabalho real realizado<\/span><\/strong><span>\u00a0por dispositivo e o\u00a0<\/span><strong><span>trabalho por dispositivo quando operado em condi\u00e7\u00f5es isentr\u00f3picas<\/span><\/strong><span>\u00a0(no caso de turbinas).\u00a0Essa rela\u00e7\u00e3o \u00e9 conhecida como\u00a0<\/span><strong><span>efici\u00eancia isentr\u00f3pica de turbina \/ compressor \/ bico<\/span><\/strong><span>\u00a0.<\/span><\/p>\n<p><span>Esses par\u00e2metros descrevem com que efici\u00eancia uma turbina, compressor ou bico se aproxima de um dispositivo isentr\u00f3pico correspondente.\u00a0Este par\u00e2metro reduz a efici\u00eancia geral e a produ\u00e7\u00e3o do trabalho.\u00a0Para turbinas, o valor de\u00a0<\/span><strong><em><span>\u03b7\u00a0<\/span><\/em><\/strong><strong><em><sub><span>T<\/span><\/sub><\/em><\/strong><span>\u00a0\u00e9 tipicamente de 0,7 a 0,9 (70-90%).<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-Efficiency-equations.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-17298 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-Efficiency-equations.png\" alt=\"Efici\u00eancia isentr\u00f3pica - equa\u00e7\u00f5es\" width=\"532\" height=\"357\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-Efficiency-equations.png\" \/><\/a><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-40 lgc-tablet-grid-40 lgc-mobile-grid-100 lgc-equal-heights  lgc-last\">\n<div class=\"inside-grid-column\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-compression.png\"><img loading=\"lazy\" class=\"aligncenter size-medium wp-image-17268 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-compression-274x300.png\" alt=\"Compress\u00e3o isentr\u00f3pica vs. adiab\u00e1tica\" width=\"274\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-compression-274x300.png\" \/><\/a><\/p>\n<figure id=\"attachment_17267\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-17267\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-expansion.png\"><img loading=\"lazy\" class=\"size-medium wp-image-17267 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-expansion-276x300.png\" alt=\"Expans\u00e3o isentr\u00f3pica vs. adiab\u00e1tica\" width=\"276\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-expansion-276x300.png\" \/><\/a><figcaption id=\"caption-attachment-17267\" class=\"wp-caption-text\"><span>O processo isentr\u00f3pico \u00e9 um caso especial de processos adiab\u00e1ticos.\u00a0\u00c9 um processo adiab\u00e1tico revers\u00edvel.\u00a0Um processo isentr\u00f3pico tamb\u00e9m pode ser chamado de processo de entropia constante.<\/span><\/figcaption><\/figure>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Exemplo: Efici\u00eancia isentr\u00f3pica da turbina<\/span><\/h2>\n<figure id=\"attachment_17267\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-17267\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-expansion.png\"><img loading=\"lazy\" class=\"size-medium wp-image-17267 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-expansion-276x300.png\" alt=\"Expans\u00e3o isentr\u00f3pica vs. adiab\u00e1tica\" width=\"276\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Isentropic-vs.-adiabatic-expansion-276x300.png\" \/><\/a><figcaption id=\"caption-attachment-17267\" class=\"wp-caption-text\"><span>O processo isentr\u00f3pico \u00e9 um caso especial de processos adiab\u00e1ticos.\u00a0\u00c9 um processo adiab\u00e1tico revers\u00edvel.\u00a0Um processo isentr\u00f3pico tamb\u00e9m pode ser chamado de processo de entropia constante.<\/span><\/figcaption><\/figure>\n<p><span>Assuma uma\u00a0<\/span><strong><span>expans\u00e3o isentr\u00f3pica<\/span><\/strong><span>\u00a0de h\u00e9lio (3 \u2192 4) em uma turbina a g\u00e1s.\u00a0Nessas turbinas, o est\u00e1gio de alta press\u00e3o recebe g\u00e1s (ponto 3 na figura; p\u00a0<\/span><sub><span>3<\/span><\/sub><span>\u00a0=\u00a0<\/span><strong><span>6,7 MPa<\/span><\/strong><span>\u00a0; T\u00a0<\/span><sub><span>3<\/span><\/sub><span>\u00a0= 1190 K (917 \u00b0 C)) de um trocador de calor e o esgota em outro trocador de calor, onde a press\u00e3o de sa\u00edda \u00e9 p\u00a0<\/span><sub><span>4<\/span><\/sub><span>\u00a0=\u00a0<\/span><strong><span>2,78 MPa<\/span><\/strong><span>\u00a0(ponto 4)\u00a0<\/span><strong><span>.\u00a0<\/span><\/strong><span>A temperatura (para o processo isentr\u00f3pico) do g\u00e1s na sa\u00edda da turbina \u00e9 T\u00a0<\/span><sub><span>4s<\/span><\/sub><span>\u00a0= 839 K (566 \u00b0 C).<\/span><\/p>\n<p><strong><span>Calcule<\/span><\/strong><span>\u00a0o trabalho realizado por esta turbina e calcule a temperatura real na sa\u00edda da turbina, quando a\u00a0<\/span><strong><span>efici\u00eancia isentr\u00f3pica da turbina<\/span><\/strong><span>\u00a0for\u00a0<\/span><strong><span>\u03b7\u00a0<\/span><\/strong><strong><sub><span>T<\/span><\/sub><\/strong><strong><span>\u00a0= 0,91 (91%)<\/span><\/strong><span>\u00a0.<\/span><\/p>\n<p><strong><span>Solu\u00e7\u00e3o:<\/span><\/strong><\/p>\n<p><span>A partir da primeira lei da termodin\u00e2mica, o trabalho realizado pela turbina em um processo isentr\u00f3pico pode ser calculado a partir de:<\/span><\/p>\n<p><strong><span>W\u00a0<\/span><\/strong><strong><sub><span>T<\/span><\/sub><\/strong><strong><span>\u00a0= h\u00a0<\/span><\/strong><strong><sub><span>3<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; h\u00a0<\/span><\/strong><strong><sub><span>4s<\/span><\/sub><\/strong><strong><span>\u00a0\u00a0\u00a0\u00a0\u00a0\u2192 W\u00a0<\/span><\/strong><strong><sub><span>Ts<\/span><\/sub><\/strong><strong><span>\u00a0=\u00a0<\/span><em><span>c\u00a0<\/span><\/em><\/strong><strong><em><sub><span>p<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0(T\u00a0<\/span><\/em><\/strong><strong><em><sub><span>3<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0&#8211; T\u00a0<\/span><\/em><\/strong><strong><em><sub><span>4s<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0)<\/span><\/em><\/strong><\/p>\n<p><span>Pela Lei do G\u00e1s Ideal, sabemos que o calor molar espec\u00edfico de um g\u00e1s ideal monat\u00f4mico \u00e9:<\/span><\/p>\n<p><strong><em><span>C\u00a0<\/span><\/em><\/strong><strong><em><sub><span>v<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0= 3 \/ 2R = 12,5 J \/ mol K<\/span><\/em><\/strong><span>\u00a0e<\/span><strong><em><span>\u00a0C\u00a0<\/span><\/em><\/strong><strong><em><sub><span>p<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0= C\u00a0<\/span><\/em><\/strong><strong><em><sub><span>v<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0+ R = 5 \/ 2R = 20,8 J \/ mol K<\/span><\/em><\/strong><\/p>\n<p><span>Transferimos as capacidades de calor espec\u00edficas em unidades de\u00a0<\/span><strong><span>J \/ kg K via:<\/span><\/strong><\/p>\n<p><strong><em><span>c\u00a0<\/span><\/em><\/strong><strong><em><sub><span>p<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0= C\u00a0<\/span><\/em><\/strong><strong><em><sub><span>p<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0.\u00a01 \/ M (peso molar de h\u00e9lio) = 20,8 x 4,10\u00a0<\/span><\/em><\/strong><strong><em><sup><span>-3<\/span><\/sup><\/em><\/strong><strong><em><span>\u00a0= 5200 J \/ kg K<\/span><\/em><\/strong><\/p>\n<p><span>O trabalho realizado pela turbina a g\u00e1s no processo isentr\u00f3pico \u00e9 ent\u00e3o:<\/span><\/p>\n<p><strong><em><span>W\u00a0<\/span><\/em><\/strong><strong><em><sub><span>T, s<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0= c\u00a0<\/span><\/em><\/strong><strong><em><sub><span>p<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0(\u00a0<\/span><\/em><\/strong><strong><em><sub><span>T3<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0&#8211;\u00a0<\/span><\/em><\/strong><strong><em><sub><span>T4s<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0) = 5200 x (1190 &#8211; 839) = 1,825 MJ \/ kg<\/span><\/em><\/strong><\/p>\n<p><span>O trabalho real realizado pela turbina a g\u00e1s no processo adiab\u00e1tico \u00e9 ent\u00e3o:<\/span><br \/>\n<strong><em><span>WT\u00a0<\/span><\/em><\/strong><strong><em><sub><span>, real<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0=\u00a0<\/span><\/em><\/strong><strong><em><sub><span>cp<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0(\u00a0<\/span><\/em><\/strong><strong><em><sub><span>T3<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0&#8211;\u00a0<\/span><\/em><\/strong><strong><em><sub><span>T4s<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0).\u00a0<\/span><\/em><\/strong><strong><em><span>\u03b7\u00a0<\/span><\/em><\/strong><strong><em><sub><span>T<\/span><\/sub><\/em><\/strong>\u00a0<strong><em><span>= 5200 x (1190 &#8211; 839) x 0,91 = 1,661 MJ \/ kg<\/span><\/em><\/strong><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Expans\u00e3o Livre &#8211; Expans\u00e3o Joule<\/span><\/h2>\n<p><span>Esses s\u00e3o\u00a0<\/span><strong><span>processos adiab\u00e1ticos<\/span><\/strong><span>\u00a0nos quais\u00a0<\/span><strong><span>nenhuma transfer\u00eancia de calor<\/span><\/strong><span>\u00a0ocorre entre o sistema e seu ambiente e\u00a0<\/span><strong><span>nenhum trabalho \u00e9 realizado<\/span><\/strong><span>\u00a0no sistema.\u00a0Esses tipos de processos adiab\u00e1ticos s\u00e3o chamados de\u00a0<\/span><strong><span>expans\u00e3o livre<\/span><\/strong><span>\u00a0.\u00a0\u00c9 um\u00a0<\/span><strong><span>processo irrevers\u00edvel<\/span><\/strong><span>\u00a0no qual um g\u00e1s se expande para uma c\u00e2mara evacuada isolada.\u00a0\u00c9 tamb\u00e9m chamado de\u00a0<\/span><strong><span>expans\u00e3o Joule<\/span><\/strong><span>\u00a0.\u00a0Para um g\u00e1s ideal, a temperatura n\u00e3o muda (consulte:\u00a0<\/span><a title=\"Segunda Lei de Joule\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/ideal-gas-law\/joules-second-law\/\"><span>Segunda Lei de Joule<\/span><\/a><span>\u00a0), no entanto, gases reais sofrem uma mudan\u00e7a de temperatura durante a expans\u00e3o livre.\u00a0Na expans\u00e3o livre Q = W = 0, e a primeira lei exige que:<\/span><\/p>\n<p><strong><span>dE\u00a0<\/span><\/strong><strong><sub><span>int<\/span><\/sub><\/strong><strong><span>\u00a0= 0<\/span><\/strong><\/p>\n<p><span>Uma expans\u00e3o livre n\u00e3o pode ser plotada em um diagrama PV, porque o processo \u00e9 r\u00e1pido, n\u00e3o quase est\u00e1tico.\u00a0Os estados intermedi\u00e1rios n\u00e3o s\u00e3o estados de equil\u00edbrio e, portanto, a press\u00e3o n\u00e3o est\u00e1 claramente definida.<\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n<div><\/div>\n<div><\/div>\n<div>\n<p>&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;.<\/p>\n<p>Este artigo \u00e9 baseado na tradu\u00e7\u00e3o autom\u00e1tica do artigo original em ingl\u00eas. Para mais informa\u00e7\u00f5es, consulte o artigo em ingl\u00eas. Voc\u00ea pode nos ajudar. Se voc\u00ea deseja corrigir a tradu\u00e7\u00e3o, envie-a para: translations@nuclear-power.com ou preencha o formul\u00e1rio de tradu\u00e7\u00e3o on-line. Agradecemos sua ajuda, atualizaremos a tradu\u00e7\u00e3o o mais r\u00e1pido poss\u00edvel. Obrigado.<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Um processo adiab\u00e1tico \u00e9 um processo termodin\u00e2mico, no qual n\u00e3o h\u00e1 transfer\u00eancia de calor para dentro ou para fora do sistema (Q = 0). O sistema pode ser considerado perfeitamente isolado. Engenharia T\u00e9rmica Processo Adiab\u00e1tico Um\u00a0processo adiab\u00e1tico\u00a0\u00e9 um\u00a0processo termodin\u00e2mico\u00a0, no qual n\u00e3o\u00a0h\u00e1 transfer\u00eancia de calor para\u00a0dentro ou para fora do sistema (Q = 0).\u00a0O sistema &#8230; <a title=\"O que \u00e9 processo adiab\u00e1tico &#8211; defini\u00e7\u00e3o\" class=\"read-more\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-processo-adiabatico-definicao\/\" aria-label=\"More on O que \u00e9 processo adiab\u00e1tico &#8211; defini\u00e7\u00e3o\">Ler mais<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[14],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v15.4 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>O que \u00e9 processo adiab\u00e1tico - defini\u00e7\u00e3o<\/title>\n<meta name=\"description\" content=\"Um processo adiab\u00e1tico \u00e9 um processo termodin\u00e2mico, no qual n\u00e3o h\u00e1 transfer\u00eancia de calor para dentro ou para fora do sistema (Q = 0). 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