{"id":48713,"date":"2019-11-11T23:14:42","date_gmt":"2019-11-11T22:14:42","guid":{"rendered":"https:\/\/www.thermal-engineering.org\/o-que-e-escala-de-pressao-unidade-de-pressao-definicao\/"},"modified":"2020-01-30T10:27:37","modified_gmt":"2020-01-30T09:27:37","slug":"o-que-e-escala-de-pressao-unidade-de-pressao-definicao","status":"publish","type":"post","link":"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-escala-de-pressao-unidade-de-pressao-definicao\/","title":{"rendered":"O que \u00e9 Escala de Press\u00e3o &#8211; Unidade de Press\u00e3o &#8211; Defini\u00e7\u00e3o"},"content":{"rendered":"<div class=\"su-quote su-quote-style-default\">\n<div class=\"su-quote-inner su-clearfix\">Existem v\u00e1rias escalas de press\u00e3o e unidades de press\u00e3o.\u00a0A unidade SI de press\u00e3o e estresse \u00e9 o pascal.\u00a0A unidade padr\u00e3o no sistema ingl\u00eas \u00e9 a for\u00e7a da libra por polegada quadrada (psi).\u00a0Engenharia T\u00e9rmica<\/div>\n<\/div>\n<div class=\"su-divider su-divider-style-dotted\"><\/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>Balan\u00e7as de press\u00e3o &#8211; Unidades de press\u00e3o<\/h2>\n<h2>Pascal &#8211; Unidade de Press\u00e3o<\/h2>\n<p>Como foi discutido, a\u00a0<strong>unidade SI<\/strong>\u00a0de\u00a0<a title=\"O que \u00e9 press\u00e3o - F\u00edsica\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/thermodynamic-properties\/what-is-pressure-physics\/\"><strong>press\u00e3o<\/strong><\/a>\u00a0e estresse \u00e9 o\u00a0<strong>pascal<\/strong>\u00a0.<\/p>\n<ul>\n<li><strong>1 pascal 1 N \/ m\u00a0<sup>2<\/sup>\u00a0= 1 kg \/ (ms\u00a0<sup>2<\/sup>\u00a0)<\/strong><\/li>\n<\/ul>\n<p>Pascal \u00e9 definido como um newton por metro quadrado.\u00a0No entanto, para a maioria dos problemas de engenharia, \u00e9 uma unidade relativamente pequena, portanto, \u00e9 conveniente trabalhar com m\u00faltiplos do pascal: o\u00a0<strong>kPa<\/strong>\u00a0, a\u00a0<strong>barra<\/strong>\u00a0e o\u00a0<strong>MPa<\/strong>\u00a0.<\/p>\n<ul>\n<li><strong>1 MPa 10\u00a0<sup>6<\/sup>\u00a0N \/ m\u00a0<sup>2<\/sup><\/strong><\/li>\n<li><strong>1 bar 10\u00a0<sup>5<\/sup>\u00a0N \/ m\u00a0<sup>2<\/sup><\/strong><\/li>\n<li><strong>1 kPa 10\u00a0<sup>3<\/sup>\u00a0N \/ m\u00a0<sup>2<\/sup><\/strong><\/li>\n<\/ul>\n<p>A unidade de medida denominada\u00a0<strong>atmosfera padr\u00e3o<\/strong>\u00a0(\u00a0<strong>atm<\/strong>\u00a0) \u00e9 definida como:<\/p>\n<ul>\n<li><strong>1 atm = 101,33 kPa<\/strong><\/li>\n<\/ul>\n<p>A atmosfera padr\u00e3o aproxima-se da press\u00e3o m\u00e9dia ao n\u00edvel do mar na latitude de 45 \u00b0 N. Observe que h\u00e1 uma diferen\u00e7a entre a\u00a0<strong>atmosfera padr\u00e3o<\/strong>\u00a0(atm) e a\u00a0<strong>atmosfera t\u00e9cnica<\/strong>\u00a0(em).<\/p>\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<p><span>Uma atmosfera t\u00e9cnica \u00e9 uma unidade de press\u00e3o n\u00e3o SI igual a um quilograma-for\u00e7a por cent\u00edmetro quadrado.<\/span><\/p>\n<ul>\n<li><strong><span>1 a = 14,2 psi<\/span><\/strong><\/li>\n<\/ul>\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<h2><b><span>Bar &#8211; Unidade de Press\u00e3o<\/span><\/b><\/h2>\n<p><span>A\u00a0<\/span><strong><span>barra<\/span><\/strong><span>\u00a0\u00e9 uma unidade m\u00e9trica de\u00a0<\/span><strong><span>press\u00e3o<\/span><\/strong><span>\u00a0.\u00a0N\u00e3o faz parte do Sistema Internacional de Unidades (SI).\u00a0A\u00a0<\/span><strong><span>barra<\/span><\/strong><span>\u00a0\u00e9 comumente usada na\u00a0<\/span><strong><span>ind\u00fastria<\/span><\/strong><span>\u00a0e na\u00a0<\/span><strong><span>meteorologia<\/span><\/strong><span>\u00a0, e um instrumento usado na meteorologia para medir a press\u00e3o atmosf\u00e9rica \u00e9 chamado bar\u00f4metro.<\/span><\/p>\n<p><span>Uma barra \u00e9 exatamente igual a\u00a0<\/span><strong><em><span>100 000 Pa<\/span><\/em><\/strong><span>\u00a0e \u00e9 ligeiramente menor que a press\u00e3o atmosf\u00e9rica m\u00e9dia na Terra ao n\u00edvel do mar (\u00a0<\/span><em><span>1 bar = 0,9869 atm).\u00a0<\/span><\/em><span>A press\u00e3o atmosf\u00e9rica \u00e9 geralmente dada em milibares, onde a press\u00e3o padr\u00e3o do n\u00edvel do mar \u00e9 definida como 1013 mbar, 1,013 bar ou 101,3 (kPa).<\/span><\/p>\n<p><span>\u00c0s vezes, &#8220;Bar (a)&#8221; e &#8220;bara&#8221; s\u00e3o usados \u200b\u200bpara indicar press\u00f5es absolutas e &#8220;bar (g)&#8221; e &#8220;barg&#8221; para press\u00f5es de man\u00f4metro.<\/span><\/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>Press\u00f5es t\u00edpicas em engenharia &#8211; Exemplos<\/span><\/h2>\n<p><span>O\u00a0<\/span><strong><span>pascal (Pa)<\/span><\/strong><span>\u00a0como uma unidade de medida de press\u00e3o \u00e9 amplamente utilizado em todo o mundo e substituiu amplamente a\u00a0unidade de\u00a0<\/span><strong><span>libras por polegada quadrada (psi)<\/span><\/strong><span>\u00a0, exceto em alguns pa\u00edses que ainda usam o sistema de medi\u00e7\u00e3o imperial, incluindo os Estados Unidos.\u00a0Para a maioria dos problemas de engenharia, o pascal (Pa) \u00e9 uma unidade relativamente pequena, portanto, \u00e9 conveniente trabalhar com m\u00faltiplos do pascal: o kPa, o MPa ou a barra.\u00a0A lista a seguir resume alguns exemplos:<\/span><\/p>\n<ul>\n<li><span>Normalmente, a maioria das\u00a0<\/span><strong><span>usinas nucleares<\/span><\/strong><span>\u00a0opera\u00a0<\/span><strong><span>turbinas a vapor de condensa\u00e7\u00e3o de v\u00e1rios est\u00e1gios<\/span><\/strong><span>\u00a0.\u00a0Essas turbinas descarregam\u00a0<\/span><a title=\"Propriedades do Steam - O que \u00e9 o Steam\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-o-steam-propriedades-do-steam-definicao\/\"><span>vapor<\/span><\/a><span>\u00a0a uma press\u00e3o bem abaixo da atmosf\u00e9rica (por exemplo, 0,08 bar ou 8 kPa ou 1,16 psia) e em um estado parcialmente condensado.\u00a0Em unidades relativas, \u00e9 uma press\u00e3o manom\u00e9trica negativa de cerca de &#8211; 0,92 bar, &#8211; 92 kPa ou &#8211; 13,54 psig.<\/span><\/li>\n<li><span>A\u00a0<\/span><strong><span>press\u00e3o atmosf\u00e9rica padr\u00e3o<\/span><\/strong><span>\u00a0aproxima-se da press\u00e3o m\u00e9dia ao n\u00edvel do mar na latitude de 45 \u00b0 N. A\u00a0<\/span><strong><span>press\u00e3o atmosf\u00e9rica padr\u00e3o<\/span><\/strong><span>\u00a0\u00e9 definida ao n\u00edvel do mar a\u00a0<\/span><em><span>273\u00a0<\/span><\/em><em><sup><span>o<\/span><\/sup><\/em><em><span>\u00a0K (0\u00a0<\/span><\/em><em><sup><span>o<\/span><\/sup><\/em><em><span>\u00a0C)<\/span><\/em><span>\u00a0e \u00e9:<\/span>\n<ul>\n<li><strong><em><span>101325 Pa<\/span><\/em><\/strong><\/li>\n<li><strong><em><span>1.01325 bar<\/span><\/em><\/strong><\/li>\n<li><strong><em><span>14.696 psi<\/span><\/em><\/strong><\/li>\n<li><strong><em><span>760 mmHg<\/span><\/em><\/strong><\/li>\n<li><strong><em><span>760 torr<\/span><\/em><\/strong><\/li>\n<\/ul>\n<\/li>\n<li><span>A sobrepress\u00e3o de pneus de carro \u00e9 de cerca de 2,5 bar, 0,25 MPa ou 36 psig.<\/span><\/li>\n<li><span>Caldeira de tubos de inc\u00eandio para locomotivas a vapor: 150\u2013250 psig<\/span><\/li>\n<li><span>Um est\u00e1gio de alta press\u00e3o da turbina a vapor de condensa\u00e7\u00e3o na usina nuclear opera em estado estacion\u00e1rio com condi\u00e7\u00f5es de entrada de 6 MPa (60 bar ou 870 psig), t = 275,6 \u00b0 C, x = 1<\/span><\/li>\n<li><span>Um\u00a0<\/span><a title=\"BWR - Reator de \u00e1gua fervente\" href=\"https:\/\/www.nuclear-power.com\/bwr-boiling-water-reactor\/\"><strong><span>reator de \u00e1gua fervente<\/span><\/strong><\/a><span>\u00a0\u00e9 resfriado e moderado por\u00a0<\/span><a title=\"Propriedades da \u00c1gua\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-of-water\/\"><span>\u00e1gua<\/span><\/a><span>\u00a0como um PWR, mas a uma\u00a0<\/span><strong><span>press\u00e3o mais baixa<\/span><\/strong><span>\u00a0(por exemplo, 7MPa, 70 bar ou 1015 psig), que permite que a \u00e1gua ferva dentro do vaso de press\u00e3o produzindo o vapor que aciona as turbinas.<\/span><\/li>\n<li><a title=\"PWR - Reator de \u00e1gua pressurizada\" href=\"https:\/\/www.nuclear-power.com\/pwr-pressurized-water-reactor\/\"><strong><span>Os reatores de \u00e1gua pressurizada<\/span><\/strong><\/a><span>\u00a0s\u00e3o resfriados e moderados por<\/span><a title=\"L\u00edquido saturado e sub-resfriado\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-steam-what-is-steam\/saturated-and-subcooled-liquid\/\"><span>\u00a0\u00e1gua l\u00edquida de alta press\u00e3o<\/span><\/a><span>\u00a0(por exemplo, 16MPa, 160 bar ou 2320 psig).\u00a0A essa press\u00e3o, a \u00e1gua ferve a aproximadamente 350 \u00b0 C (662 \u00b0 F), o que fornece margem de sub-resfriamento de cerca de 25 \u00b0 C.<\/span><\/li>\n<li><span>O\u00a0<\/span><a title=\"Reator Supercr\u00edtico de \u00c1gua - SCWR\" href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/reactor-types\/supercritical-water-reactor-scwr\/\"><strong><span>reator de \u00e1gua supercr\u00edtico (SCWR)<\/span><\/strong><\/a><span>\u00a0\u00e9 operado a\u00a0<\/span><strong><span>press\u00e3o supercr\u00edtica<\/span><\/strong><span>\u00a0.\u00a0O termo supercr\u00edtico neste contexto refere-se ao\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-of-water\/critical-point-of-water\/\"><strong><span>ponto cr\u00edtico<\/span><\/strong><\/a><span>\u00a0termodin\u00e2mico\u00a0<a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-of-water\/critical-point-of-water\/\"><strong>da \u00e1gua<\/strong><\/a>\u00a0(T\u00a0<\/span><sub><span>CR<\/span><\/sub><span>\u00a0= 374 \u00b0 C; p\u00a0<\/span><sub><span>CR<\/span><\/sub><span>\u00a0= 22,1 MPa)<\/span><\/li>\n<li><strong><span>Inje\u00e7\u00e3o direta de combust\u00edvel em trilho comum:<\/span><\/strong><span>\u00a0em motores a diesel, ele possui um\u00a0<strong>trilho de combust\u00edvel de<\/strong>\u00a0alta press\u00e3o (acima de 1 000 bar ou 100 MPa ou 14500 psi).<\/span><\/li>\n<\/ul>\n<\/div>\n<\/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>Existem v\u00e1rias escalas de press\u00e3o e unidades de press\u00e3o.\u00a0A unidade SI de press\u00e3o e estresse \u00e9 o pascal.\u00a0A unidade padr\u00e3o no sistema ingl\u00eas \u00e9 a for\u00e7a da libra por polegada quadrada (psi).\u00a0Engenharia T\u00e9rmica Balan\u00e7as de press\u00e3o &#8211; Unidades de press\u00e3o Pascal &#8211; Unidade de Press\u00e3o Como foi discutido, a\u00a0unidade SI\u00a0de\u00a0press\u00e3o\u00a0e estresse \u00e9 o\u00a0pascal\u00a0. 1 pascal &#8230; <a title=\"O que \u00e9 Escala de Press\u00e3o &#8211; Unidade de Press\u00e3o &#8211; Defini\u00e7\u00e3o\" class=\"read-more\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-escala-de-pressao-unidade-de-pressao-definicao\/\" aria-label=\"More on O que \u00e9 Escala de Press\u00e3o &#8211; Unidade de Press\u00e3o &#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 Escala de Press\u00e3o - Unidade de Press\u00e3o - Defini\u00e7\u00e3o<\/title>\n<meta name=\"description\" content=\"Existem v\u00e1rias escalas de press\u00e3o e unidades de press\u00e3o. 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