{"id":43911,"date":"2019-10-14T02:26:19","date_gmt":"2019-10-14T01:26:19","guid":{"rendered":"https:\/\/www.thermal-engineering.org\/quest-ce-que-external-vs-internal-nusselt-number-definition\/"},"modified":"2020-02-17T10:35:05","modified_gmt":"2020-02-17T09:35:05","slug":"quest-ce-que-external-vs-internal-nusselt-number-definition","status":"publish","type":"post","link":"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-que-external-vs-internal-nusselt-number-definition\/","title":{"rendered":"Qu&#8217;est-ce que External vs Internal &#8211; Nusselt Number &#8211; Definition"},"content":{"rendered":"<div class=\"su-quote su-quote-style-default\">\n<div class=\"su-quote-inner su-clearfix\">Externe vs interne &#8211; Nombre de Nusselt &#8211; Calcul du coefficient de transfert de chaleur par convection.\u00a0De ce point de vue, on distingue: flux interne, flux externe.\u00a0G\u00e9nie thermique<\/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>Classification des r\u00e9gimes d&#8217;\u00e9coulement<\/h2>\n<p>Le\u00a0<a title=\"R\u00e9gime d'\u00e9coulement\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/flow-regime\/\"><strong>r\u00e9gime d&#8217;\u00e9coulement<\/strong><\/a>\u00a0peut \u00e9galement \u00eatre class\u00e9 en fonction de la\u00a0\u00a0<strong>g\u00e9om\u00e9trie d&#8217;un conduit<\/strong>\u00a0\u00a0ou de la zone d&#8217;\u00e9coulement.\u00a0De ce point de vue, on distingue:<\/p>\n<ul>\n<li><a title=\"Flux interne\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/internal-flow\/\"><strong>Flux interne<\/strong><\/a><\/li>\n<li><a title=\"Flux externe\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/external-flow\/\"><strong>Flux externe<\/strong><\/a><\/li>\n<\/ul>\n<p><strong>Le flux interne<\/strong>\u00a0\u00a0est un flux pour lequel le fluide est confin\u00e9 par une surface.\u00a0Une connaissance d\u00e9taill\u00e9e du comportement des r\u00e9gimes d&#8217;\u00e9coulement interne est\u00a0\u00a0<strong>importante en ing\u00e9nierie<\/strong>\u00a0, car les tuyaux circulaires peuvent supporter des pressions \u00e9lev\u00e9es et sont donc utilis\u00e9s pour transporter des liquides.\u00a0Par ailleurs, le\u00a0\u00a0<strong>flux externe<\/strong>\u00a0\u00a0est un flux dans lequel les couches limites se d\u00e9veloppent librement, sans contrainte impos\u00e9e par les surfaces adjacentes.\u00a0Une connaissance d\u00e9taill\u00e9e du comportement des\u00a0\u00a0\u00a0r\u00e9gimes d&#8217;\u00a0<strong>\u00e9coulement externes<\/strong>\u00a0est\u00a0\u00a0<strong>importante, notamment en a\u00e9ronautique<\/strong>\u00a0\u00a0et en\u00a0\u00a0<strong>a\u00e9rodynamique<\/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>D\u00e9bit externe<\/span><\/h2>\n<p><span>En\u00a0<\/span><a title=\"Dynamique des fluides\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/\"><span>dynamique des fluides<\/span><\/a><span>\u00a0,\u00a0\u00a0<\/span><a title=\"D\u00e9bit externe\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/external-flow\/\"><strong><span>l&#8217;\u00e9coulement externe<\/span><\/strong><\/a><span>\u00a0\u00a0est un tel \u00e9coulement dans lequel\u00a0\u00a0<\/span><a title=\"Couche limite\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-que-la-couche-limite-definition\/\"><strong><span>les couches limites se<\/span><\/strong><\/a><span>\u00a0\u00a0d\u00e9veloppent librement, sans contraintes impos\u00e9es par\u00a0\u00a0<\/span><strong><span>les surfaces adjacentes<\/span><\/strong><span>\u00a0.\u00a0Par rapport au flux interne, les flux externes pr\u00e9sentent\u00a0\u00a0<\/span><strong><span>des effets tr\u00e8s visqueux<\/span><\/strong><span>\u00a0\u00a0confin\u00e9s \u00e0 des \u00ab\u00a0<\/span><strong><span>couches limites<\/span><\/strong><span>\u00a0\u00bb \u00e0 croissance rapide\u00a0dans la r\u00e9gion d&#8217;entr\u00e9e, ou \u00e0 des couches de cisaillement minces le long de la surface solide.\u00a0En cons\u00e9quence, il existera toujours une r\u00e9gion de l&#8217;\u00e9coulement \u00e0 l&#8217;ext\u00e9rieur de la couche limite.\u00a0Dans cette r\u00e9gion, la vitesse, la temp\u00e9rature et \/ ou la concentration ne changent pas et leurs gradients peuvent \u00eatre n\u00e9glig\u00e9s.<\/span><\/p>\n<p><span>Cet effet provoque la\u00a0\u00a0<\/span><strong><span>couche limite<\/span><\/strong><span>\u00a0\u00a0\u00e0 l&#8217;\u00a0expansion et l&#8217;\u00e9paisseur de la\u00a0couche limite se\u00a0rapporte \u00e0 la\u00a0viscosit\u00e9 cin\u00e9matique du fluide.<\/span><\/p>\n<p><span>Cela est d\u00e9montr\u00e9 sur l&#8217;image suivante.\u00a0Loin du corps, le flux est presque non visqueux, il peut \u00eatre d\u00e9fini comme le flux d&#8217;un fluide autour d&#8217;un corps qui est compl\u00e8tement submerg\u00e9.<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Boundary-layer-on-flat-plate.png?d484e7\"><img loading=\"lazy\" class=\"aligncenter size-large wp-image-14390 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Boundary-layer-on-flat-plate-1024x357.png?d484e7\" alt=\"Couche limite sur plaque plate\" width=\"669\" height=\"233\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Boundary-layer-on-flat-plate-1024x357.png?d484e7\" \/><\/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>D\u00e9bit externe &#8211; plaque plate<\/span><\/h2>\n<p><span>Le\u00a0<\/span><a title=\"Quel est le nombre de Nusselt\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-nusselt-number\/\"><strong><span>nombre<\/span><\/strong>\u00a0<\/a><span>moyen de\u00a0<a title=\"Quel est le nombre de 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>\u00a0sur toute la plaque est d\u00e9termin\u00e9 par:<\/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=\"flux laminaire - plaque plate - nombre 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>Cette relation donne le\u00a0<\/span><strong><a title=\"Coefficient de transfert de chaleur par convection\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-quun-coefficient-de-transfert-de-chaleur-par-convection-definition\/\"><span>coefficient de transfert de chaleur<\/span><\/a><\/strong><span>\u00a0moyen\u00a0pour toute la plaque lorsque le flux est\u00a0<\/span><a title=\"\u00c9coulement laminaire - \u00c9coulement visqueux\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-que-lecoulement-laminaire-ecoulement-visqueux-definition\/\"><span>laminaire<\/span><\/a><span>\u00a0sur toute la plaque.<\/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=\"\u00e9coulement turbulent - plaque plate - nombre 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>Cette relation donne le\u00a0<\/span><a title=\"Coefficient de transfert de chaleur par convection\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-quun-coefficient-de-transfert-de-chaleur-par-convection-definition\/\"><strong><span>coefficient de transfert thermique<\/span><\/strong><\/a><span>\u00a0moyen\u00a0pour la plaque enti\u00e8re uniquement lorsque l&#8217;\u00e9coulement est\u00a0<\/span><a title=\"\u00c9coulement turbulent\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-quun-ecoulement-turbulent-definition\/\"><strong><span>turbulent<\/span><\/strong>\u00a0<\/a><span>sur toute la plaque, ou lorsque la\u00a0r\u00e9gion d&#8217;\u00a0<\/span><a title=\"\u00c9coulement laminaire - \u00c9coulement visqueux\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-que-lecoulement-laminaire-ecoulement-visqueux-definition\/\"><span>\u00e9coulement laminaire<\/span><\/a><span>\u00a0de la plaque est trop petite par rapport \u00e0 la r\u00e9gion d&#8217;\u00e9coulement turbulent.<\/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>Flux interne<\/span><\/h2>\n<figure id=\"attachment_14394\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-14394\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Internal-Flow.png\"><img loading=\"lazy\" class=\"size-medium wp-image-14394 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Internal-Flow-300x269.png\" alt=\"Flux interne\" width=\"300\" height=\"269\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Internal-Flow-300x269.png\" \/><\/a><figcaption id=\"caption-attachment-14394\" class=\"wp-caption-text\"><span>Source: White Frank M., Fluid Mechanics, McGraw-Hill Education, 7e \u00e9dition, f\u00e9vrier 2010, ISBN: 978-0077422417<\/span><\/figcaption><\/figure>\n<p><span>En\u00a0<\/span><a title=\"Dynamique des fluides\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/\"><span>dynamique des fluides<\/span><\/a><span>\u00a0,\u00a0<\/span><a title=\"Flux interne\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/internal-flow\/\"><strong><span>le flux interne<\/span><\/strong><\/a><span>\u00a0est un flux pour lequel le fluide est\u00a0\u00a0<\/span><strong><span>confin\u00e9 par une surface<\/span><\/strong><span>\u00a0.\u00a0Une connaissance d\u00e9taill\u00e9e du comportement des r\u00e9gimes d&#8217;\u00e9coulement internes est importante en ing\u00e9nierie, car les tuyaux circulaires peuvent r\u00e9sister \u00e0 des pressions \u00e9lev\u00e9es et sont donc utilis\u00e9s pour transporter des liquides.\u00a0Les conduits non circulaires sont utilis\u00e9s pour transporter des gaz \u00e0 basse pression, tels que l&#8217;air dans les syst\u00e8mes de refroidissement et de chauffage.\u00a0La configuration du flux interne est une g\u00e9om\u00e9trie pratique pour les fluides de chauffage et de refroidissement utilis\u00e9s dans les technologies de conversion d&#8217;\u00e9nergie telles que\u00a0\u00a0<\/span><a title=\"Centrale nucl\u00e9aire\" href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/\"><span>les centrales nucl\u00e9aires<\/span><\/a><span>\u00a0.<\/span><\/p>\n<p><span>Pour\u00a0\u00a0<\/span><a title=\"Flux interne\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/internal-flow\/\"><span>le r\u00e9gime d&#8217;\u00e9coulement interne,<\/span><\/a><span>\u00a0\u00a0une\u00a0\u00a0<\/span><strong><span>r\u00e9gion d&#8217;entr\u00e9e<\/span><\/strong><span>\u00a0\u00a0est typique.\u00a0Dans cette r\u00e9gion, un flux amont presque non visqueux converge et p\u00e9n\u00e8tre dans le tube.\u00a0Pour caract\u00e9riser cette r\u00e9gion, la\u00a0\u00a0<\/span><strong><span>longueur d&#8217;entr\u00e9e hydrodynamique<\/span><\/strong><span>\u00a0\u00a0est introduite et est approximativement \u00e9gale \u00e0:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/hydrodynamic-entrance-length.png?d484e7\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-14416 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/hydrodynamic-entrance-length.png?d484e7\" alt=\"longueur d'entr\u00e9e hydrodynamique\" width=\"365\" height=\"69\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/hydrodynamic-entrance-length.png?d484e7\" \/><\/a><\/p>\n<p><span>La longueur maximale d&#8217;entr\u00e9e hydrodynamique, \u00e0\u00a0\u00a0<\/span><strong><span>Re\u00a0<\/span><sub><span>D, crit<\/span><\/sub><span>\u00a0\u00a0= 2300<\/span><\/strong><span>\u00a0\u00a0(\u00a0<\/span><strong><span>flux laminaire<\/span><\/strong><span>\u00a0), est L\u00a0<\/span><sub><span>e<\/span><\/sub><span>\u00a0\u00a0= 138d, o\u00f9 D est le diam\u00e8tre du tuyau.\u00a0Il s&#8217;agit de la plus longue dur\u00e9e de d\u00e9veloppement possible.\u00a0Dans\u00a0\u00a0<\/span><strong><span>un \u00e9coulement turbulent<\/span><\/strong><span>\u00a0, les couches limites croissent plus rapidement et L\u00a0<\/span><sub><span>e<\/span><\/sub><span>\u00a0\u00a0est relativement plus courte.\u00a0Pour tout probl\u00e8me donn\u00e9,\u00a0\u00a0<\/span><strong><span>L\u00a0<\/span><sub><span>e<\/span><\/sub><span>\u00a0\u00a0\/ D<\/span><\/strong><span>\u00a0\u00a0doit \u00eatre\u00a0\u00a0<\/span><strong><span>v\u00e9rifi\u00e9<\/span><\/strong><span>\u00a0\u00a0pour voir si L\u00a0<\/span><sub><span>e<\/span><\/sub><span>\u00a0\u00a0est n\u00e9gligeable par rapport \u00e0 la longueur du tuyau.\u00a0\u00c0 une distance finie de l&#8217;entr\u00e9e, les effets d&#8217;entr\u00e9e peuvent \u00eatre n\u00e9glig\u00e9s, car les couches limites fusionnent et le noyau non visqueux dispara\u00eet.\u00a0L&#8217;\u00e9coulement du tube est alors\u00a0\u00a0<\/span><strong><span>compl\u00e8tement d\u00e9velopp\u00e9<\/span><\/strong><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>\u00c9coulement laminaire interne &#8211; nombre de Nusselt<\/span><\/h2>\n<p><strong><span>Temp\u00e9rature de surface constante<\/span><\/strong><\/p>\n<p><span>Dans\u00a0<\/span><a title=\"\u00c9coulement laminaire - \u00c9coulement visqueux\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-que-lecoulement-laminaire-ecoulement-visqueux-definition\/\"><strong><span>un \u00e9coulement laminaire<\/span><\/strong><\/a><span>\u00a0dans un tube \u00e0 temp\u00e9rature de surface constante, le facteur de friction et le\u00a0<\/span><a title=\"Coefficient de transfert de chaleur par convection\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-quun-coefficient-de-transfert-de-chaleur-par-convection-definition\/\"><strong><span>coefficient de transfert de chaleur<\/span><\/strong><\/a><span>\u00a0restent constants dans la r\u00e9gion compl\u00e8tement d\u00e9velopp\u00e9e.<\/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=\"D\u00e9bit laminaire - Tube circulaire - temp\u00e9rature\" 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>Flux de chaleur de surface constant<\/span><\/strong><\/p>\n<p><span>Par cons\u00e9quent, pour\u00a0<\/span><strong><span>un \u00e9coulement laminaire<\/span><\/strong><span>\u00a0pleinement d\u00e9velopp\u00e9\u00a0dans un tube circulaire soumis \u00e0\u00a0<\/span><a title=\"Densit\u00e9 de flux thermique - Flux thermique\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/heat-flux-density-thermal-flux\/\"><span>un flux thermique de<\/span><\/a><span>\u00a0surface constant\u00a0, le nombre de Nusselt est une constante.\u00a0Il n&#8217;y a aucune d\u00e9pendance sur les\u00a0<a title=\"Qu'est-ce que le num\u00e9ro Prandtl\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-prandtl-number\/\">nombres de\u00a0<\/a><\/span><a title=\"Le num\u00e9ro de Reynold\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/reynolds-number\/\"><span>Reynolds<\/span><\/a><span>\u00a0ou de\u00a0<\/span><a title=\"Qu'est-ce que le num\u00e9ro 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=\"Flux laminaire - Tube circulaire - flux\" 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>D\u00e9bit turbulent interne &#8211; nombre de Nusselt<\/span><\/h2>\n<p><span>Voir aussi:\u00a0<\/span><a title=\"\u00c9quation Dittus-Boelter\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/convection-convective-heat-transfer\/dittus-boelter-equation\/\"><span>\u00c9quation Dittus-Boelter<\/span><\/a><\/p>\n<p><span>Pour\u00a0<\/span><a title=\"\u00c9coulement turbulent\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-quun-ecoulement-turbulent-definition\/\"><span>un \u00e9coulement turbulent<\/span><\/a><span>\u00a0compl\u00e8tement d\u00e9velopp\u00e9 (hydrodynamiquement et thermiquement)\u00a0\u00a0\u00a0dans un tube circulaire lisse, le\u00a0<\/span><a title=\"Quel est le nombre de Nusselt\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-nusselt-number\/\"><span>nombre de Nusselt<\/span><\/a><span>\u00a0local\u00a0\u00a0\u00a0peut \u00eatre obtenu \u00e0 partir de l&#8217;\u00a0<\/span><strong><span>\u00e9quation<\/span><\/strong><span>\u00a0bien connue de\u00a0\u00a0<strong>Dittus-Boelter<\/strong>\u00a0.\u00a0L&#8217;\u00a0\u00a0<\/span><strong><span>\u00e9quation Dittus ?? Boelter<\/span><\/strong><span>\u00a0\u00a0est facile \u00e0 r\u00e9soudre mais est moins pr\u00e9cise lorsqu&#8217;il existe une grande diff\u00e9rence de temp\u00e9rature \u00e0 travers le\u00a0\u00a0<\/span><a title=\"Dynamique des fluides\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/\"><span>fluide<\/span><\/a><span>\u00a0\u00a0et est moins pr\u00e9cise pour les tubes rugueux (de nombreuses applications commerciales), car elle est adapt\u00e9e aux tubes lisses.<\/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=\"\u00c9quation Dittus-Boelter - Formule\" 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>La\u00a0\u00a0<\/span><a title=\"\u00c9quation Dittus-Boelter\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/convection-convective-heat-transfer\/dittus-boelter-equation\/\"><strong><span>corr\u00e9lation Dittus-Boelter<\/span><\/strong><\/a><span>\u00a0\u00a0peut \u00eatre utilis\u00e9e pour des diff\u00e9rences de temp\u00e9rature petites \u00e0 mod\u00e9r\u00e9es,\u00a0<\/span><sub><span>paroi<\/span><\/sub><span>\u00a0\u00a0T &#8211; T\u00a0<\/span><sub><span>moyenne<\/span><\/sub><span>\u00a0, toutes les propri\u00e9t\u00e9s \u00e9tant \u00e9valu\u00e9es \u00e0 une temp\u00e9rature moyenne T\u00a0<\/span><sub><span>moyenne<\/span><\/sub><span>\u00a0.<\/span><\/p>\n<p><span>Pour les flux caract\u00e9ris\u00e9s par de grandes variations de propri\u00e9t\u00e9s, les corrections (par exemple un facteur de correction de viscosit\u00e9\u00a0\u00a0<\/span><strong><span>\u03bc \/ \u03bc\u00a0<\/span><\/strong><strong><sub><span>paroi<\/span><\/sub><\/strong><span>\u00a0) doivent \u00eatre prises en compte, par exemple, comme le\u00a0recommandent\u00a0<\/span><a title=\"\u00c9quation de Sieder-Tate\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/convection-convective-heat-transfer\/sieder-tate-equation\/\"><span>Sieder et 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>Calcul du nombre de Nusselt \u00e0 l&#8217;aide de l&#8217;\u00e9quation de Dittus-Boelter<\/span><\/h2>\n<p><span>Pour un \u00e9coulement turbulent pleinement d\u00e9velopp\u00e9 (hydrodynamiquement et thermiquement) dans un tube circulaire lisse, le\u00a0<\/span><strong><span>nombre de Nusselt<\/span><\/strong><span>\u00a0local\u00a0peut \u00eatre obtenu \u00e0 partir de l&#8217;\u00a0<\/span><strong><span>\u00e9quation<\/span><\/strong><span>\u00a0bien connue de\u00a0<strong>Dittus ?? Boelter<\/strong>\u00a0.<\/span><\/p>\n<p><span>Pour calculer le\u00a0<\/span><strong><span>nombre de Nusselt<\/span><\/strong><span>\u00a0, nous devons savoir:<\/span><\/p>\n<ul>\n<li><span>le\u00a0<\/span><a title=\"Le num\u00e9ro de Reynold\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/reynolds-number\/\"><span>nombre de Reynolds<\/span><\/a><span>\u00a0, qui est\u00a0<\/span><strong><span>Re\u00a0<\/span><sub><span>Dh<\/span><\/sub><span>\u00a0= 575600<\/span><\/strong><\/li>\n<li><span>le\u00a0<\/span><a title=\"Qu'est-ce que le num\u00e9ro Prandtl\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-prandtl-number\/\"><span>nombre de Prandtl<\/span><\/a><span>\u00a0, qui est\u00a0<\/span><strong><span>Pr = 0,89<\/span><\/strong><\/li>\n<\/ul>\n<p><span>Le\u00a0<\/span><strong><span>nombre de Nusselt<\/span><\/strong><span>\u00a0pour la convection forc\u00e9e \u00e0 l&#8217;int\u00e9rieur du canal de carburant est alors \u00e9gal \u00e0:<\/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=\"num\u00e9ro nusselt - exemple\" 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\"><\/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>Cet article est bas\u00e9 sur la traduction automatique de l&#8217;article original en anglais. Pour plus d&#8217;informations, voir l&#8217;article en anglais. Pouvez vous nous aider Si vous souhaitez corriger la traduction, envoyez-la \u00e0 l&#8217;adresse: translations@nuclear-power.com ou remplissez le formulaire de traduction en ligne. Nous appr\u00e9cions votre aide, nous mettrons \u00e0 jour la traduction le plus rapidement possible. Merci<\/p>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Externe vs interne &#8211; Nombre de Nusselt &#8211; Calcul du coefficient de transfert de chaleur par convection.\u00a0De ce point de vue, on distingue: flux interne, flux externe.\u00a0G\u00e9nie thermique Classification des r\u00e9gimes d&#8217;\u00e9coulement Le\u00a0r\u00e9gime d&#8217;\u00e9coulement\u00a0peut \u00e9galement \u00eatre class\u00e9 en fonction de la\u00a0\u00a0g\u00e9om\u00e9trie d&#8217;un conduit\u00a0\u00a0ou de la zone d&#8217;\u00e9coulement.\u00a0De ce point de vue, on distingue: Flux interne &#8230; <a title=\"Qu&#8217;est-ce que External vs Internal &#8211; Nusselt Number &#8211; Definition\" class=\"read-more\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-que-external-vs-internal-nusselt-number-definition\/\" aria-label=\"En savoir plus sur Qu&#8217;est-ce que External vs Internal &#8211; Nusselt Number &#8211; Definition\">Lire la suite<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[8],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v15.4 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Qu&#039;est-ce que External vs Internal - Nusselt Number - Definition<\/title>\n<meta name=\"description\" content=\"Externe vs interne - Nombre de Nusselt - Calcul du coefficient de transfert de chaleur par convection. 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