{"id":43915,"date":"2019-10-14T02:45:52","date_gmt":"2019-10-14T01:45:52","guid":{"rendered":"https:\/\/www.thermal-engineering.org\/quest-ce-que-laminar-vs-turbulent-nusselt-number-definition\/"},"modified":"2020-02-17T10:36:03","modified_gmt":"2020-02-17T09:36:03","slug":"quest-ce-que-laminar-vs-turbulent-nusselt-number-definition","status":"publish","type":"post","link":"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-que-laminar-vs-turbulent-nusselt-number-definition\/","title":{"rendered":"Qu&#8217;est ce que Laminar vs Turbulent &#8211; Nusselt Number &#8211; Definition"},"content":{"rendered":"<div class=\"su-quote su-quote-style-default\">\n<div class=\"su-quote-inner su-clearfix\">Laminar vs Turbulent &#8211; Nombre de Nusselt &#8211; Calcul du coefficient de transfert de chaleur par convection.\u00a0De ce point de vue, on distingue: flux laminaire et turbulent<\/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><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=\"Le num\u00e9ro de Reynold\" width=\"300\" height=\"151\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Reynolds-Number-300x151.png\" \/><\/a>Une autre classification des\u00a0<strong>r\u00e9gimes d&#8217;\u00e9coulement,<\/strong>\u00a0g\u00e9n\u00e9ralement plus courante,\u00a0\u00a0\u00a0est la forme et le type des\u00a0<strong>lignes<\/strong>\u00a0de\u00a0\u00a0<strong>courant<\/strong>\u00a0.\u00a0Tout \u00e9coulement de fluide est class\u00e9 dans l&#8217;une des deux grandes cat\u00e9gories.\u00a0Le flux de fluide peut \u00eatre laminaire ou turbulent. Ces deux cat\u00e9gories sont donc les suivantes:<\/p>\n<ul>\n<li><a title=\"Flux laminaire - flux visqueux\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-que-lecoulement-laminaire-ecoulement-visqueux-definition\/\"><strong>\u00c9coulement laminaire<\/strong><\/a><\/li>\n<li><a title=\"\u00c9coulement turbulent\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-quun-ecoulement-turbulent-definition\/\"><strong>\u00c9coulement turbulent<\/strong><\/a><\/li>\n<\/ul>\n<p><strong>\u00c9coulement laminaire<\/strong>\u00a0\u00a0est caract\u00e9ris\u00e9 par\u00a0\u00a0<strong>lisse<\/strong>\u00a0\u00a0ou dans\u00a0 des\u00a0<strong>chemins r\u00e9guliers<\/strong>\u00a0\u00a0de particules de fluide.\u00a0Par cons\u00e9quent, l&#8217;\u00e9coulement laminaire est \u00e9galement appel\u00e9\u00a0\u00a0<strong>\u00e9coulement fluide ou visqueux<\/strong>\u00a0.\u00a0Contrairement \u00e0 l&#8217;\u00e9coulement laminaire, l&#8217;\u00e9coulement\u00a0\u00a0<strong>turbulent<\/strong>\u00a0\u00a0est caract\u00e9ris\u00e9 par le\u00a0\u00a0<strong>mouvement irr\u00e9gulier<\/strong>\u00a0\u00a0des particules du fluide.\u00a0Le fluide turbulent ne coule pas dans les couches parall\u00e8les, le m\u00e9lange lat\u00e9ral est tr\u00e8s \u00e9lev\u00e9 et il y a une rupture entre les couches.\u00a0<strong>La plupart des flux industriels<\/strong>\u00a0, notamment ceux du g\u00e9nie nucl\u00e9aire,\u00a0\u00a0<strong>sont turbulents<\/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>\u00c9coulement laminaire<\/span><\/h2>\n<p><span>Dans la dynamique des fluides,\u00a0\u00a0<\/span><strong><span>l&#8217;\u00e9coulement laminaire<\/span><\/strong><span>\u00a0\u00a0est caract\u00e9ris\u00e9 par\u00a0\u00a0<\/span><strong><span>des trajectoires r\u00e9guli\u00e8res ou r\u00e9guli\u00e8res<\/span><\/strong><span>\u00a0\u00a0des particules du fluide, contrairement \u00e0 l&#8217;\u00e9coulement turbulent, qui est caract\u00e9ris\u00e9 par le mouvement irr\u00e9gulier des particules du fluide.\u00a0Le fluide s&#8217;\u00e9coule en\u00a0\u00a0<\/span><strong><span>couches parall\u00e8les<\/span><\/strong><span>\u00a0\u00a0(avec un m\u00e9lange lat\u00e9ral minimal), sans interruption entre les couches.\u00a0Par cons\u00e9quent, le flux laminaire est \u00e9galement appel\u00e9\u00a0\u00a0<\/span><strong><span>flux simplifi\u00e9 ou flux visqueux<\/span><\/strong><span>\u00a0.<\/span><\/p>\n<p><span>Le terme \u00e9coulement a\u00e9rodynamique est descriptif de l&#8217;\u00e9coulement car, dans un \u00e9coulement laminaire, des couches d&#8217;eau s&#8217;\u00e9coulant les unes sur les autres \u00e0 des vitesses diff\u00e9rentes sans pratiquement aucun m\u00e9lange entre les couches, les particules fluides se d\u00e9placent selon des trajectoires ou des lignes de courant d\u00e9finies et observables.<\/span><\/p>\n<p><span>Lorsqu&#8217;un fluide s&#8217;\u00e9coule \u00e0 travers un canal ferm\u00e9 tel qu&#8217;un tuyau ou entre deux plaques plates, l&#8217;un ou l&#8217;autre des deux types de flux (flux laminaire ou flux turbulent) peut se produire en fonction de la\u00a0\u00a0<\/span><strong><span>vitesse<\/span><\/strong><span>\u00a0, de la\u00a0\u00a0<\/span><strong><span>viscosit\u00e9<\/span><\/strong><span>\u00a0\u00a0du fluide et de la\u00a0\u00a0<\/span><strong><span>taille du tuyau<\/span><\/strong><span>\u00a0.\u00a0<\/span><strong><span>L&#8217;\u00e9coulement laminaire a<\/span><\/strong><span>\u00a0\u00a0tendance \u00e0 se produire \u00e0\u00a0\u00a0<\/span><strong><span>des vitesses plus faibles<\/span><\/strong><span>\u00a0\u00a0et \u00e0\u00a0\u00a0<\/span><strong><span>une viscosit\u00e9 \u00e9lev\u00e9e<\/span><\/strong><span>\u00a0.\u00a0D&#8217;un autre c\u00f4t\u00e9, un \u00e9coulement turbulent a tendance \u00e0 se produire \u00e0 des vitesses plus \u00e9lev\u00e9es et \u00e0 une faible viscosit\u00e9.<\/span><\/p>\n<p><span>Puisque l&#8217;\u00e9coulement laminaire n&#8217;est courant que dans les cas o\u00f9 le canal d&#8217;\u00e9coulement est relativement petit, le fluide se d\u00e9place lentement et sa viscosit\u00e9 est relativement \u00e9lev\u00e9e, l&#8217;\u00e9coulement laminaire n&#8217;est pas courant dans les processus industriels.\u00a0La plupart des flux industriels, en particulier ceux du g\u00e9nie nucl\u00e9aire, sont turbulents.\u00a0N\u00e9anmoins, l&#8217;\u00e9coulement laminaire\u00a0\u00a0<\/span><strong><span>se produit \u00e0 n&#8217;importe quel nombre de Reynolds\u00a0<\/span><\/strong><span>\u00a0pr\u00e8s des limites solides dans une couche mince juste adjacente \u00e0 la surface, cette couche est g\u00e9n\u00e9ralement appel\u00e9e sous-\u00a0<\/span><strong><span>\u00a0couche laminaire<\/span><\/strong><span>\u00a0\u00a0et elle est tr\u00e8s importante dans le transfert de chaleur.<\/span><\/p>\n<p><span>Voir aussi:\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><\/p>\n<p><span>Voir aussi:\u00a0<\/span><a title=\"Nombre critique de Reynolds\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/reynolds-number\/critical-reynolds-number\/\"><span>Nombre de Reynolds critique<\/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>\u00c9coulement laminaire externe &#8211; nombre de Nusselt<\/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<\/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>\u00c9coulement turbulent<\/span><\/h2>\n<p><span>En dynamique des fluides, l&#8217;\u00a0\u00a0<\/span><a title=\"\u00c9coulement turbulent\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-quun-ecoulement-turbulent-definition\/\"><strong><span>\u00e9coulement turbulent<\/span><\/strong><\/a><span>\u00a0\u00a0est caract\u00e9ris\u00e9 par le\u00a0<\/span><strong><span>\u00a0mouvement irr\u00e9gulier<\/span><\/strong><span>\u00a0\u00a0des particules (on peut dire\u00a0\u00a0<\/span><strong><span>chaotique<\/span><\/strong><span>\u00a0) du fluide.\u00a0Contrairement au\u00a0\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>flux laminaire,<\/span><\/strong><\/a><span>\u00a0\u00a0le fluide ne coule pas en couches parall\u00e8les, le m\u00e9lange lat\u00e9ral est tr\u00e8s \u00e9lev\u00e9 et il y a une rupture entre les couches.\u00a0La turbulence est \u00e9galement caract\u00e9ris\u00e9e par la\u00a0\u00a0<\/span><strong><span>recirculation, les tourbillons et le caract\u00e8re al\u00e9atoire apparent<\/span><\/strong><span>\u00a0.\u00a0Dans un \u00e9coulement turbulent, la vitesse du fluide en un point subit continuellement des changements d&#8217;amplitude et de direction.<\/span><\/p>\n<p><span>Une connaissance d\u00e9taill\u00e9e du comportement du r\u00e9gime d&#8217;\u00e9coulement turbulent est importante en g\u00e9nie, car la\u00a0\u00a0<\/span><strong><span>plupart des \u00e9coulements industriels<\/span><\/strong><span>\u00a0, en particulier ceux du\u00a0<\/span><a title=\"Ing\u00e9nierie nucl\u00e9aire\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/\"><span>\u00a0g\u00e9nie nucl\u00e9aire,<\/span><\/a><span>\u00a0\u00a0sont\u00a0\u00a0<\/span><strong><span>turbulents<\/span><\/strong><span>\u00a0.\u00a0Malheureusement, le caract\u00e8re hautement intermittent et irr\u00e9gulier des turbulences\u00a0\u00a0<\/span><strong><span>complique toutes les analyses<\/span><\/strong><span>\u00a0.\u00a0En fait, la turbulence est souvent consid\u00e9r\u00e9e comme le\u00a0<\/span><strong><span>\u00a0\u00abdernier probl\u00e8me non r\u00e9solu de la physique math\u00e9matique classique\u00bb.<\/span><\/strong><\/p>\n<p><span>Le principal outil disponible pour leur analyse est l&#8217;\u00a0\u00a0<\/span><strong><span>analyse CFD<\/span><\/strong><span>\u00a0.\u00a0CFD est une branche de la m\u00e9canique des fluides qui utilise l&#8217;analyse num\u00e9rique et des algorithmes pour r\u00e9soudre et analyser les probl\u00e8mes impliquant des \u00e9coulements de fluide turbulents.\u00a0Il est largement admis que les\u00a0\u00a0<\/span><a title=\"\u00c9quations de Navier-Stokes\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/navier-stokes-equations\/\"><strong><span>\u00e9quations de Navier-Stokes<\/span><\/strong><\/a><span>\u00a0\u00a0(ou les\u00a0<a title=\"\u00c9quations de Navier-Stokes\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/navier-stokes-equations\/\"><strong>\u00e9quations<\/strong><\/a>\u00a0simplifi\u00e9es de\u00a0\u00a0<\/span><strong><span>Navier-Stokes moyenn\u00e9es par Reynolds<\/span><\/strong><span>\u00a0) sont capables de pr\u00e9senter des solutions turbulentes, et ces \u00e9quations sont la base de pratiquement tous les codes 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>D\u00e9bit turbulent externe &#8211; nombre de Nusselt<\/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\/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>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\">\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>Laminar vs Turbulent &#8211; Nombre de Nusselt &#8211; Calcul du coefficient de transfert de chaleur par convection.\u00a0De ce point de vue, on distingue: flux laminaire et turbulent Classification des r\u00e9gimes d&#8217;\u00e9coulement Une autre classification des\u00a0r\u00e9gimes d&#8217;\u00e9coulement,\u00a0g\u00e9n\u00e9ralement plus courante,\u00a0\u00a0\u00a0est la forme et le type des\u00a0lignes\u00a0de\u00a0\u00a0courant\u00a0.\u00a0Tout \u00e9coulement de fluide est class\u00e9 dans l&#8217;une des deux grandes cat\u00e9gories.\u00a0Le &#8230; <a title=\"Qu&#8217;est ce que Laminar vs Turbulent &#8211; Nusselt Number &#8211; Definition\" class=\"read-more\" href=\"https:\/\/www.thermal-engineering.org\/fr\/quest-ce-que-laminar-vs-turbulent-nusselt-number-definition\/\" aria-label=\"En savoir plus sur Qu&#8217;est ce que Laminar vs Turbulent &#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 Laminar vs Turbulent - Nusselt Number - Definition<\/title>\n<meta name=\"description\" content=\"Laminar vs Turbulent - Nombre de Nusselt - Calcul du coefficient de transfert de chaleur par convection. 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