{"id":47483,"date":"2019-11-05T04:22:16","date_gmt":"2019-11-05T03:22:16","guid":{"rendered":"https:\/\/www.thermal-engineering.org\/o-que-e-laminar-vs-turbulent-nusselt-number-definicao\/"},"modified":"2020-01-23T14:47:34","modified_gmt":"2020-01-23T13:47:34","slug":"o-que-e-laminar-vs-turbulent-nusselt-number-definicao","status":"publish","type":"post","link":"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-laminar-vs-turbulent-nusselt-number-definicao\/","title":{"rendered":"O que \u00e9 Laminar vs Turbulent &#8211; Nusselt Number &#8211; Defini\u00e7\u00e3o"},"content":{"rendered":"<div class=\"su-quote su-quote-style-default\">\n<div class=\"su-quote-inner su-clearfix\">Laminar vs Turbulento &#8211; N\u00famero de Nusselt &#8211; C\u00e1lculo do coeficiente de transfer\u00eancia de calor por convec\u00e7\u00e3o.\u00a0Deste ponto de vista, distinguimos: escoamento laminar e turbulento<\/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>Classifica\u00e7\u00e3o dos regimes de fluxo<\/h2>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Reynolds-Number.png\"><img loading=\"lazy\" class=\"alignright size-medium wp-image-14465 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Reynolds-Number-300x151.png\" alt=\"N\u00famero de Reynolds\" width=\"300\" height=\"151\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Reynolds-Number-300x151.png\" \/><\/a>Outra classifica\u00e7\u00e3o geralmente mais comum dos\u00a0<strong>regimes<\/strong>\u00a0de\u00a0\u00a0<strong>fluxo<\/strong>\u00a0\u00a0\u00e9 de acordo com a forma e o tipo de\u00a0<strong>linhas<\/strong>\u00a0de\u00a0\u00a0<strong>fluxo<\/strong>\u00a0.\u00a0Todo o fluxo de fluido \u00e9 classificado em uma de duas grandes categorias.\u00a0O fluxo de fluido pode ser laminar ou turbulento e, portanto, essas duas categorias s\u00e3o:<\/p>\n<ul>\n<li><a title=\"Fluxo Laminar - Fluxo Viscoso\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-fluxo-laminar-fluxo-viscoso-definicao\/\"><strong>Fluxo laminar<\/strong><\/a><\/li>\n<li><a title=\"Fluxo turbulento\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-fluxo-turbulento-definicao\/\"><strong>Fluxo turbulento<\/strong><\/a><\/li>\n<\/ul>\n<p><strong>O fluxo laminar<\/strong>\u00a0\u00a0\u00e9 caracterizado por\u00a0\u00a0<strong>caminhos\u00a0<\/strong><strong>suaves<\/strong>\u00a0\u00a0ou\u00a0\u00a0<strong>regulares<\/strong>\u00a0\u00a0de part\u00edculas do fluido.\u00a0Portanto, o fluxo laminar tamb\u00e9m \u00e9 conhecido como\u00a0\u00a0<strong>fluxo aerodin\u00e2mico ou viscoso<\/strong>\u00a0.\u00a0Ao contr\u00e1rio do fluxo laminar, o fluxo\u00a0\u00a0<strong>turbulento<\/strong>\u00a0\u00a0\u00e9 caracterizado pelo\u00a0\u00a0<strong>movimento irregular<\/strong>\u00a0\u00a0das part\u00edculas do fluido.\u00a0O fluido turbulento n\u00e3o flui em camadas paralelas, a mistura lateral \u00e9 muito alta e h\u00e1 uma ruptura entre as camadas.\u00a0<strong>A maioria dos fluxos industriais<\/strong>\u00a0, especialmente os de engenharia nuclear,\u00a0\u00a0<strong>s\u00e3o turbulentos<\/strong> .<\/p>\n<\/div>\n<\/div>\n<p>&nbsp;<\/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<h2><span>Fluxo laminar<\/span><\/h2>\n<p><span>Na din\u00e2mica de fluidos,\u00a0\u00a0<\/span><strong><span>o fluxo laminar<\/span><\/strong><span>\u00a0\u00a0\u00e9 caracterizado por\u00a0\u00a0<\/span><strong><span>trajetos lisos ou regulares<\/span><\/strong><span>\u00a0\u00a0das part\u00edculas do fluido, em contraste com o fluxo turbulento, caracterizado pelo movimento irregular das part\u00edculas do fluido.\u00a0O fluido flui em\u00a0\u00a0<\/span><strong><span>camadas paralelas<\/span><\/strong><span>\u00a0\u00a0(com mistura lateral m\u00ednima), sem interrup\u00e7\u00e3o entre as camadas.\u00a0Portanto, o fluxo laminar tamb\u00e9m \u00e9 conhecido como\u00a0\u00a0<\/span><strong><span>fluxo aerodin\u00e2mico ou viscoso<\/span><\/strong><span>\u00a0.<\/span><\/p>\n<p><span>O termo fluxo de corrente de fluxo \u00e9 descritivo do fluxo porque, no fluxo laminar, camadas de \u00e1gua fluindo umas sobre as outras em velocidades diferentes, praticamente sem mistura entre as camadas, as part\u00edculas de fluido se movem em caminhos ou linhas de fluxo definidos e observ\u00e1veis.<\/span><\/p>\n<p><span>Quando um fluido est\u00e1 fluindo atrav\u00e9s de um canal fechado, como um tubo ou entre duas placas planas, pode ocorrer um dos dois tipos de fluxo (fluxo laminar ou fluxo turbulento), dependendo da\u00a0\u00a0<\/span><strong><span>velocidade<\/span><\/strong><span>\u00a0,\u00a0\u00a0<\/span><strong><span>viscosidade<\/span><\/strong><span>\u00a0\u00a0do fluido e do\u00a0\u00a0<\/span><strong><span>tamanho do tubo<\/span><\/strong><span>\u00a0.\u00a0<\/span><strong><span>O fluxo laminar<\/span><\/strong><span>\u00a0\u00a0tende a ocorrer em\u00a0\u00a0<\/span><strong><span>velocidades mais baixas<\/span><\/strong><span>\u00a0\u00a0e com\u00a0\u00a0<\/span><strong><span>alta viscosidade<\/span><\/strong><span>\u00a0.\u00a0Por outro lado, o fluxo turbulento tende a ocorrer em velocidades mais altas e baixa viscosidade.<\/span><\/p>\n<p><span>Como o fluxo laminar \u00e9 comum apenas nos casos em que o canal de fluxo \u00e9 relativamente pequeno, o fluido se move lentamente e sua viscosidade \u00e9 relativamente alta, o fluxo laminar n\u00e3o \u00e9 comum em processos industriais.\u00a0A maioria dos fluxos industriais, especialmente os de engenharia nuclear, s\u00e3o turbulentos.\u00a0No entanto, o fluxo laminar\u00a0\u00a0<\/span><strong><span>ocorre em qualquer n\u00famero de Reynolds\u00a0<\/span><\/strong><span>\u00a0pr\u00f3ximo a limites s\u00f3lidos em uma camada fina adjacente \u00e0 superf\u00edcie, essa camada \u00e9 geralmente chamada de\u00a0<\/span><strong><span>\u00a0subcamada laminar<\/span><\/strong><span>\u00a0\u00a0e \u00e9 muito importante na transfer\u00eancia de calor.<\/span><\/p>\n<p><span>Veja tamb\u00e9m:\u00a0<\/span><a title=\"N\u00famero de Reynolds\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/reynolds-number\/\"><span>N\u00famero de Reynolds<\/span><\/a><\/p>\n<p><span>Veja tamb\u00e9m:\u00a0<\/span><a title=\"N\u00famero cr\u00edtico de Reynolds\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/reynolds-number\/critical-reynolds-number\/\"><span>N\u00famero cr\u00edtico de Reynolds<\/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\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Fluxo Laminar Externo &#8211; N\u00famero Nusselt<\/span><\/h2>\n<p><span>O\u00a0<\/span><a title=\"O que \u00e9 o n\u00famero Nusselt\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-nusselt-number\/\"><strong><span>n\u00famero<\/span><\/strong>\u00a0<\/a><span>m\u00e9dio de\u00a0<a title=\"O que \u00e9 o n\u00famero Nusselt\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-nusselt-number\/\"><strong>Nusselt<\/strong><\/a>\u00a0em toda a placa \u00e9 determinado por:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/laminar-flow-flat-plate-nusselt-number.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-20504 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/laminar-flow-flat-plate-nusselt-number.png\" alt=\"fluxo laminar - placa plana - n\u00famero nusselt\" width=\"626\" height=\"235\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/laminar-flow-flat-plate-nusselt-number.png\" \/><\/a><\/p>\n<p><span>Essa rela\u00e7\u00e3o fornece o\u00a0<\/span><strong><a title=\"Coeficiente de transfer\u00eancia de calor por convec\u00e7\u00e3o\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-coeficiente-de-transferencia-de-calor-por-conveccao-definicao\/\"><span>coeficiente<\/span><\/a><\/strong><span>\u00a0m\u00e9dio de\u00a0<strong><a title=\"Coeficiente de transfer\u00eancia de calor por convec\u00e7\u00e3o\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-coeficiente-de-transferencia-de-calor-por-conveccao-definicao\/\">transfer\u00eancia de calor<\/a><\/strong>\u00a0para toda a placa quando o fluxo \u00e9\u00a0<\/span><a title=\"Fluxo Laminar - Fluxo Viscoso\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-fluxo-laminar-fluxo-viscoso-definicao\/\"><span>laminar<\/span><\/a><span>\u00a0sobre toda a placa.<\/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>Fluxo Laminar Interno &#8211; N\u00famero de Nusselt<\/span><\/h2>\n<p><strong><span>Temperatura constante da superf\u00edcie<\/span><\/strong><\/p>\n<p><span>No\u00a0<\/span><a title=\"Fluxo Laminar - Fluxo Viscoso\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-fluxo-laminar-fluxo-viscoso-definicao\/\"><strong><span>fluxo laminar<\/span><\/strong><\/a><span>\u00a0em um tubo com temperatura constante da superf\u00edcie, o fator de atrito e o\u00a0<\/span><a title=\"Coeficiente de transfer\u00eancia de calor por convec\u00e7\u00e3o\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-coeficiente-de-transferencia-de-calor-por-conveccao-definicao\/\"><strong><span>coeficiente de transfer\u00eancia de calor<\/span><\/strong><\/a><span>\u00a0permanecem constantes na regi\u00e3o totalmente desenvolvida.<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Laminar-Flow-Circular-Tube-temperature.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-20508 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Laminar-Flow-Circular-Tube-temperature.png\" alt=\"Fluxo Laminar - Tubo Circular - temperatura\" width=\"560\" height=\"187\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Laminar-Flow-Circular-Tube-temperature.png\" \/><\/a><\/p>\n<p><strong><span>Fluxo de calor de superf\u00edcie constante<\/span><\/strong><\/p>\n<p><span>Portanto, para\u00a0<\/span><strong><span>fluxo laminar<\/span><\/strong><span>\u00a0totalmente desenvolvido\u00a0em um tubo circular sujeito a constante\u00a0<\/span><a title=\"Densidade do fluxo de calor - Fluxo t\u00e9rmico\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/heat-flux-density-thermal-flux\/\"><span>fluxo de calor na<\/span><\/a><span>\u00a0superf\u00edcie\u00a0, o n\u00famero de Nusselt \u00e9 uma constante.\u00a0N\u00e3o h\u00e1 depend\u00eancia\u00a0dos\u00a0<a title=\"O que \u00e9 o n\u00famero Prandtl\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-prandtl-number\/\">n\u00fameros de\u00a0<\/a><\/span><a title=\"N\u00famero de Reynolds\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/reynolds-number\/\"><span>Reynolds<\/span><\/a><span>\u00a0ou\u00a0<\/span><a title=\"O que \u00e9 o n\u00famero Prandtl\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-prandtl-number\/\"><span>Prandtl<\/span><\/a><span>\u00a0.<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Laminar-Flow-Circular-Tube-flux.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-20507 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Laminar-Flow-Circular-Tube-flux.png\" alt=\"Fluxo Laminar - Tubo Circular - fluxo\" width=\"532\" height=\"191\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Laminar-Flow-Circular-Tube-flux.png\" \/><\/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>Fluxo turbulento<\/span><\/h2>\n<p><span>Na din\u00e2mica de fluidos, o\u00a0\u00a0<\/span><a title=\"Fluxo turbulento\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-fluxo-turbulento-definicao\/\"><strong><span>fluxo turbulento<\/span><\/strong><\/a><span>\u00a0\u00a0\u00e9 caracterizado pelo\u00a0<\/span><strong><span>\u00a0movimento irregular<\/span><\/strong><span>\u00a0\u00a0de part\u00edculas (pode-se dizer\u00a0\u00a0<\/span><strong><span>ca\u00f3tico<\/span><\/strong><span>\u00a0) do fluido.\u00a0Ao contr\u00e1rio do\u00a0\u00a0<\/span><a title=\"Fluxo Laminar - Fluxo Viscoso\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-fluxo-laminar-fluxo-viscoso-definicao\/\"><strong><span>fluxo laminar,<\/span><\/strong><\/a><span>\u00a0\u00a0o fluido n\u00e3o flui em camadas paralelas, a mistura lateral \u00e9 muito alta e h\u00e1 uma ruptura entre as camadas.\u00a0A turbul\u00eancia tamb\u00e9m \u00e9 caracterizada por\u00a0\u00a0<\/span><strong><span>recircula\u00e7\u00e3o, redemoinhos e aleatoriedade aparente<\/span><\/strong><span>\u00a0.\u00a0No fluxo turbulento, a velocidade do fluido em um ponto est\u00e1 continuamente sofrendo altera\u00e7\u00f5es na magnitude e na dire\u00e7\u00e3o.<\/span><\/p>\n<p><span>O conhecimento detalhado do comportamento do regime de fluxo turbulento \u00e9 importante na engenharia, porque a\u00a0\u00a0<\/span><strong><span>maioria dos fluxos industriais<\/span><\/strong><span>\u00a0, especialmente os\u00a0<\/span><a title=\"Engenharia nuclear\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/\"><span>\u00a0de engenharia nuclear,<\/span><\/a><span>\u00a0\u00a0s\u00e3o\u00a0\u00a0<\/span><strong><span>turbulentos<\/span><\/strong><span>\u00a0.\u00a0Infelizmente, o car\u00e1ter altamente intermitente e irregular da turbul\u00eancia\u00a0\u00a0<\/span><strong><span>complica todas as an\u00e1lises<\/span><\/strong><span>\u00a0.\u00a0De fato, costuma-se dizer que a turbul\u00eancia \u00e9 o\u00a0<\/span><strong><span>\u00a0&#8220;\u00faltimo problema n\u00e3o resolvido da f\u00edsica matem\u00e1tica cl\u00e1ssica&#8221;.<\/span><\/strong><\/p>\n<p><span>A principal ferramenta dispon\u00edvel para sua an\u00e1lise \u00e9 a\u00a0\u00a0<\/span><strong><span>an\u00e1lise CFD<\/span><\/strong><span>\u00a0.\u00a0O CFD \u00e9 um ramo da mec\u00e2nica de fluidos que utiliza an\u00e1lise e algoritmos num\u00e9ricos para resolver e analisar problemas que envolvem fluxos de fluidos turbulentos.\u00a0\u00c9 amplamente aceito que as\u00a0\u00a0<\/span><a title=\"Equa\u00e7\u00f5es de Navier-Stokes\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/navier-stokes-equations\/\"><strong><span>equa\u00e7\u00f5es de Navier-Stokes<\/span><\/strong><\/a><span>\u00a0\u00a0(ou\u00a0<a title=\"Equa\u00e7\u00f5es de Navier-Stokes\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/navier-stokes-equations\/\"><strong>equa\u00e7\u00f5es<\/strong><\/a>\u00a0simplificadas\u00a0\u00a0<\/span><strong><span>de Navier-Stokes, com m\u00e9dia de Reynolds<\/span><\/strong><span>\u00a0) s\u00e3o capazes de exibir solu\u00e7\u00f5es turbulentas, e essas equa\u00e7\u00f5es s\u00e3o a base de praticamente todos os c\u00f3digos CFD.<\/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>Fluxo Turbulento Externo &#8211; N\u00famero Nusselt<\/span><\/h2>\n<p><span>O\u00a0<\/span><a title=\"O que \u00e9 o n\u00famero Nusselt\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-nusselt-number\/\"><strong><span>n\u00famero<\/span><\/strong>\u00a0<\/a><span>m\u00e9dio de\u00a0<a title=\"O que \u00e9 o n\u00famero Nusselt\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-nusselt-number\/\"><strong>Nusselt<\/strong><\/a>\u00a0em toda a placa \u00e9 determinado por:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/turbulent-flow-flat-plate-nusselt-number.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-20505 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/turbulent-flow-flat-plate-nusselt-number.png\" alt=\"fluxo turbulento - placa plana - n\u00famero de nusselt\" width=\"565\" height=\"243\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/turbulent-flow-flat-plate-nusselt-number.png\" \/><\/a><\/p>\n<p><span>Essa rela\u00e7\u00e3o fornece o\u00a0<\/span><a title=\"Coeficiente de transfer\u00eancia de calor por convec\u00e7\u00e3o\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-coeficiente-de-transferencia-de-calor-por-conveccao-definicao\/\"><strong><span>coeficiente<\/span><\/strong><\/a><span>\u00a0m\u00e9dio de\u00a0<a title=\"Coeficiente de transfer\u00eancia de calor por convec\u00e7\u00e3o\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-coeficiente-de-transferencia-de-calor-por-conveccao-definicao\/\"><strong>transfer\u00eancia de calor<\/strong><\/a>\u00a0para a placa inteira somente quando o fluxo \u00e9\u00a0<\/span><a title=\"Fluxo turbulento\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-fluxo-turbulento-definicao\/\"><strong><span>turbulento<\/span><\/strong>\u00a0<\/a><span>sobre a placa inteira ou quando a\u00a0regi\u00e3o de\u00a0<\/span><a title=\"Fluxo Laminar - Fluxo Viscoso\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-fluxo-laminar-fluxo-viscoso-definicao\/\"><span>fluxo laminar<\/span><\/a><span>\u00a0da placa \u00e9 muito pequena em rela\u00e7\u00e3o \u00e0 regi\u00e3o do fluxo turbulento.<\/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>Fluxo Turbulento Interno &#8211; N\u00famero Nusselt<\/span><\/h2>\n<p><span>Veja tamb\u00e9m:\u00a0<\/span><a title=\"Equa\u00e7\u00e3o de Dittus-Boelter\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/convection-convective-heat-transfer\/dittus-boelter-equation\/\"><span>Equa\u00e7\u00e3o de Dittus-Boelter<\/span><\/a><\/p>\n<p><span>Para\u00a0\u00a0um\u00a0<\/span><a title=\"Fluxo turbulento\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-fluxo-turbulento-definicao\/\"><span>fluxo turbulento<\/span><\/a><span>\u00a0totalmente desenvolvido (hidrodinamicamente e termicamente)\u00a0\u00a0em um tubo circular liso, o\u00a0<\/span><a title=\"O que \u00e9 o n\u00famero Nusselt\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-nusselt-number\/\"><span>n\u00famero<\/span><\/a><span>\u00a0local de\u00a0\u00a0<a title=\"O que \u00e9 o n\u00famero Nusselt\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-nusselt-number\/\">Nusselt<\/a>\u00a0\u00a0pode ser obtido a partir da conhecida\u00a0\u00a0<\/span><strong><span>equa\u00e7\u00e3o de Dittus-Boelter<\/span><\/strong><span>\u00a0.\u00a0A\u00a0\u00a0<\/span><strong><span>equa\u00e7\u00e3o Dittus\u00ae Boelter<\/span><\/strong><span>\u00a0\u00a0\u00e9 f\u00e1cil de resolver, mas \u00e9 menos precisa quando existe uma grande diferen\u00e7a de temperatura no\u00a0\u00a0<\/span><a title=\"Din\u00e2mica de Fluidos\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/\"><span>fluido<\/span><\/a><span>\u00a0\u00a0e \u00e9 menos precisa para tubos \u00e1speros (muitas aplica\u00e7\u00f5es comerciais), pois \u00e9 adaptada para tubos lisos.<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Dittus-Boelter-Equation-Formula.png?d484e7\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-20409 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Dittus-Boelter-Equation-Formula.png?d484e7\" alt=\"Equa\u00e7\u00e3o de Dittus-Boelter - F\u00f3rmula\" width=\"556\" height=\"278\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Dittus-Boelter-Equation-Formula.png?d484e7\" \/><\/a><\/p>\n<p><span>A\u00a0\u00a0<\/span><a title=\"Equa\u00e7\u00e3o de Dittus-Boelter\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/convection-convective-heat-transfer\/dittus-boelter-equation\/\"><strong><span>correla\u00e7\u00e3o de Dittus-Boelter<\/span><\/strong><\/a><span>\u00a0\u00a0pode ser usada para diferen\u00e7as de temperatura pequenas a moderadas, T\u00a0<\/span><sub><span>wall<\/span><\/sub><span>\u00a0\u00a0&#8211; T\u00a0<\/span><sub><span>avg<\/span><\/sub><span>\u00a0, com todas as propriedades avaliadas a uma temperatura\u00a0<\/span><sub><span>m\u00e9dia<\/span><\/sub><span>\u00a0T\u00a0<sub>avg<\/sub>\u00a0.<\/span><\/p>\n<p><span>Para fluxos caracterizados por grandes varia\u00e7\u00f5es de propriedades, as corre\u00e7\u00f5es (por exemplo, um fator de corre\u00e7\u00e3o de viscosidade\u00a0\u00a0<\/span><strong><span>\u03bc \/ \u03bc de\u00a0<\/span><\/strong><strong><sub><span>parede<\/span><\/sub><\/strong><span>\u00a0) devem ser levadas em considera\u00e7\u00e3o, por exemplo, como\u00a0recomendam\u00a0<\/span><a title=\"Equa\u00e7\u00e3o de Sieder-Tate\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/convection-convective-heat-transfer\/sieder-tate-equation\/\"><span>Sieder e Tate<\/span><\/a><span>\u00a0.<\/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>C\u00e1lculo do n\u00famero de Nusselt usando a equa\u00e7\u00e3o de Dittus-Boelter<\/span><\/h2>\n<p><span>Para um fluxo turbulento totalmente desenvolvido (hidrodinamicamente e termicamente) em um tubo circular liso, o\u00a0<\/span><strong><span>n\u00famero<\/span><\/strong><span>\u00a0local de\u00a0<strong>Nusselt<\/strong>\u00a0pode ser obtido a partir da conhecida\u00a0<\/span><strong><span>equa\u00e7\u00e3o Dittus\u00ae Boelter<\/span><\/strong><span>\u00a0.<\/span><\/p>\n<p><span>Para calcular o\u00a0<\/span><strong><span>n\u00famero de Nusselt<\/span><\/strong><span>\u00a0, precisamos saber:<\/span><\/p>\n<ul>\n<li><span>o\u00a0<\/span><a title=\"N\u00famero de Reynolds\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/reynolds-number\/\"><span>n\u00famero de Reynolds<\/span><\/a><span>\u00a0, que \u00e9\u00a0<\/span><strong><span>Re\u00a0<\/span><sub><span>Dh<\/span><\/sub><span>\u00a0= 575600<\/span><\/strong><\/li>\n<li><span>o\u00a0<\/span><a title=\"O que \u00e9 o n\u00famero Prandtl\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-prandtl-number\/\"><span>n\u00famero Prandtl<\/span><\/a><span>\u00a0, que \u00e9\u00a0<\/span><strong><span>Pr = 0,89<\/span><\/strong><\/li>\n<\/ul>\n<p><span>O\u00a0<\/span><strong><span>n\u00famero de Nusselt<\/span><\/strong><span>\u00a0para a convec\u00e7\u00e3o for\u00e7ada dentro do canal de combust\u00edvel \u00e9 ent\u00e3o igual a:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/nusselt-number-example.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-20413 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/nusselt-number-example.png\" alt=\"n\u00famero nusselt - exemplo\" width=\"387\" height=\"58\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/nusselt-number-example.png\" \/><\/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-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\">\n<p>&nbsp;<\/p>\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<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Laminar vs Turbulento &#8211; N\u00famero de Nusselt &#8211; C\u00e1lculo do coeficiente de transfer\u00eancia de calor por convec\u00e7\u00e3o.\u00a0Deste ponto de vista, distinguimos: escoamento laminar e turbulento Classifica\u00e7\u00e3o dos regimes de fluxo Outra classifica\u00e7\u00e3o geralmente mais comum dos\u00a0regimes\u00a0de\u00a0\u00a0fluxo\u00a0\u00a0\u00e9 de acordo com a forma e o tipo de\u00a0linhas\u00a0de\u00a0\u00a0fluxo\u00a0.\u00a0Todo o fluxo de fluido \u00e9 classificado em uma de duas &#8230; <a title=\"O que \u00e9 Laminar vs Turbulent &#8211; Nusselt Number &#8211; Defini\u00e7\u00e3o\" class=\"read-more\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-laminar-vs-turbulent-nusselt-number-definicao\/\" aria-label=\"More on O que \u00e9 Laminar vs Turbulent &#8211; Nusselt Number &#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 Laminar vs Turbulent - Nusselt Number - Defini\u00e7\u00e3o<\/title>\n<meta name=\"description\" content=\"Laminar vs Turbulento - N\u00famero de Nusselt - C\u00e1lculo do coeficiente de transfer\u00eancia de calor por convec\u00e7\u00e3o. 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