{"id":39961,"date":"2019-09-17T05:22:31","date_gmt":"2019-09-17T04:22:31","guid":{"rendered":"https:\/\/www.thermal-engineering.org\/que-es-un-ejemplo-de-conveccion-problema-con-la-solucion-definicion\/"},"modified":"2020-01-06T21:09:49","modified_gmt":"2020-01-06T20:09:49","slug":"que-es-un-ejemplo-de-conveccion-problema-con-la-solucion-definicion","status":"publish","type":"post","link":"https:\/\/www.thermal-engineering.org\/es\/que-es-un-ejemplo-de-conveccion-problema-con-la-solucion-definicion\/","title":{"rendered":"\u00bfQu\u00e9 es un ejemplo de convecci\u00f3n? Problema con la soluci\u00f3n: definici\u00f3n"},"content":{"rendered":"<div class=\"su-quote su-quote-style-default\">\n<div class=\"su-quote-inner su-clearfix\">Este ejemplo muestra c\u00f3mo calcular la transferencia de calor por convecci\u00f3n.\u00a0C\u00e1lculo del coeficiente de transferencia de calor y la temperatura de la superficie del revestimiento.\u00a0Ingenieria termal<\/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>Ejemplo &#8211; Convecci\u00f3n &#8211; Temperatura de la superficie del revestimiento<\/h2>\n<p><strong><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Convection-Convective-Heat-Transfer-example.png\"><img loading=\"lazy\" class=\"alignright size-medium wp-image-20406 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Convection-Convective-Heat-Transfer-example-275x300.png\" alt=\"Convecci\u00f3n - Transferencia de calor por convecci\u00f3n\" width=\"275\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Convection-Convective-Heat-Transfer-example-275x300.png\" \/><\/a><\/strong><\/p>\n<p><strong>Ejemplo &#8211; Convecci\u00f3n &#8211; Problema con la soluci\u00f3n\u00a0<\/strong><\/p>\n<p><strong>El revestimiento<\/strong>\u00a0es la capa externa de las barras de combustible, que se encuentra entre el\u00a0<strong>refrigerante<\/strong>\u00a0del\u00a0<strong>reactor<\/strong>\u00a0y el\u00a0<a title=\"Combustible nuclear\" href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/nuclear-fuel\/\"><strong>combustible nuclear<\/strong><\/a>(es decir,\u00a0<strong>las pastillas de combustible<\/strong>\u00a0).\u00a0Est\u00e1 hecho de un material resistente a la corrosi\u00f3n con una secci\u00f3n transversal de baja absorci\u00f3n para\u00a0<a title=\"Neutrones t\u00e9rmicos\" href=\"https:\/\/www.nuclear-power.com\/nuclear-power\/reactor-physics\/atomic-nuclear-physics\/fundamental-particles\/neutron\/thermal-neutron\/\">neutrones t\u00e9rmicos<\/a>\u00a0, generalmente\u00a0<strong>aleaci\u00f3n de circonio<\/strong>\u00a0.\u00a0<strong>El revestimiento<\/strong>\u00a0evita que los productos de fisi\u00f3n radiactiva escapen de la matriz de combustible al refrigerante del reactor y lo contaminen.\u00a0El revestimiento constituye una de las barreras en el\u00a0enfoque de\u00a0&#8216;\u00a0<strong>defensa en profundidad<\/strong>\u00a0&#8216;, por lo tanto, su\u00a0<strong>capacidad de enfriamiento<\/strong>\u00a0es uno de los aspectos clave de seguridad.<\/p>\n<p>Considere el revestimiento de combustible del radio interno\u00a0<strong>r\u00a0<\/strong><strong><sub>Zr, 2<\/sub><\/strong><strong>\u00a0= 0.408 cm<\/strong>\u00a0y el radio externo\u00a0<strong>r\u00a0<\/strong><strong><sub>Zr, 1<\/sub><\/strong><strong>\u00a0= 0.465 cm<\/strong>\u00a0.\u00a0En comparaci\u00f3n con el granulado de combustible, casi no hay generaci\u00f3n de calor en el revestimiento de combustible (el revestimiento se\u00a0<a href=\"https:\/\/www.nuclear-power.com\/nuclear-power\/fission\/energy-release-from-fission\/\">calienta ligeramente por radiaci\u00f3n<\/a>\u00a0).\u00a0Todo el calor generado en el combustible debe transferirse por\u00a0<a title=\"Conducci\u00f3n t\u00e9rmica - Conducci\u00f3n de calor\" href=\"https:\/\/www.thermal-engineering.org\/es\/que-es-la-conduccion-termica-conduccion-de-calor-definicion\/\"><strong>conducci\u00f3n a<\/strong><\/a>\u00a0trav\u00e9s del revestimiento y, por lo tanto, la superficie interna est\u00e1 m\u00e1s caliente que la superficie externa.<\/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>Asumir que:<\/span><\/p>\n<ul>\n<li><span>El di\u00e1metro exterior del revestimiento es:\u00a0<\/span><strong><span>d = 2 xr\u00a0<\/span><sub><span>Zr, 1<\/span><\/sub><span>\u00a0= 9,3 mm<\/span><\/strong><\/li>\n<li><span>El paso de los pasadores de combustible es:\u00a0<\/span><strong><span>p = 13 mm<\/span><\/strong><\/li>\n<li><span>La\u00a0<\/span><a title=\"Conductividad t\u00e9rmica\" href=\"https:\/\/www.thermal-engineering.org\/es\/que-es-la-conductividad-termica-definicion\/\"><span>conductividad t\u00e9rmica<\/span><\/a><span>\u00a0del\u00a0<\/span><a title=\"L\u00edquido saturado y subenfriado\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-steam-what-is-steam\/saturated-and-subcooled-liquid\/\"><span>agua saturada<\/span><\/a><span>\u00a0a 300 \u00b0 C es:\u00a0<\/span><strong><span>k\u00a0<\/span><\/strong><strong><sub><span>H2O<\/span><\/sub><\/strong><strong><span>\u00a0= 0.545 W \/ mK<\/span><\/strong><\/li>\n<li><span>La viscosidad din\u00e1mica del agua saturada a 300 \u00b0 C es:\u00a0<\/span><strong><span>\u03bc = 0.0000859 Ns \/ m\u00a0<\/span><\/strong><strong><sup><span>2<\/span><\/sup><\/strong><\/li>\n<li><span>la\u00a0<\/span><a title=\"\u00bfQu\u00e9 es la densidad? - F\u00edsica\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/thermodynamic-properties\/what-is-density-physics\/\"><span>densidad<\/span><\/a><span>\u00a0del fluido\u00a0es:\u00a0<\/span><strong><span>\u03c1 = 714 kg \/ m\u00a0<\/span><\/strong><strong><sup><span>3<\/span><\/sup><\/strong><\/li>\n<li><span>el\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/first-law-of-thermodynamics\/heat-capacity\/\"><strong><span>calor espec\u00edfico<\/span><\/strong><\/a><span>\u00a0es:\u00a0<\/span><strong><span>c\u00a0<\/span><\/strong><strong><sub><span>p<\/span><\/sub><\/strong><strong><span>\u00a0= 5,65 kJ \/ kg.K<\/span><\/strong><\/li>\n<li><span>la velocidad del flujo central es constante e igual a\u00a0<\/span><strong><span>V\u00a0<\/span><\/strong><strong><sub><span>core<\/span><\/sub><\/strong><strong><span>\u00a0= 5 m \/ s<\/span><\/strong><\/li>\n<li><span>La temperatura del refrigerante del reactor en esta coordenada axial es:\u00a0<\/span><strong><span>T a\u00a0<\/span><\/strong><strong><sub><span>granel<\/span><\/sub><\/strong><strong><span>\u00a0= 296 \u00b0 C<\/span><\/strong><\/li>\n<li><span>la tasa de calor lineal del combustible es\u00a0<\/span><strong><span>q\u00a0<\/span><\/strong><strong><sub><span>L<\/span><\/sub><\/strong><strong><span>\u00a0= 300 W \/ cm<\/span><\/strong><span>\u00a0(F\u00a0<\/span><sub><span>Q<\/span><\/sub><span>\u00a0\u2248 2.0) y, por lo tanto, la tasa de calor volum\u00e9trica es q\u00a0<\/span><sub><span>V<\/span><\/sub><span>\u00a0= 597 x 10\u00a0<\/span><sup><span>6<\/span><\/sup><span>\u00a0W \/ m\u00a0<\/span><sup><span>3<\/span><\/sup><\/li>\n<\/ul>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Hydraulic-Diameter-Fuel-Channel.png\"><img loading=\"lazy\" class=\"alignright size-medium wp-image-20407 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Hydraulic-Diameter-Fuel-Channel-254x300.png\" alt=\"Di\u00e1metro hidr\u00e1ulico - Canal de combustible\" width=\"254\" height=\"300\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Hydraulic-Diameter-Fuel-Channel-254x300.png\" \/><\/a><span>Calcule el n\u00famero de\u00a0<\/span><a title=\"\u00bfQu\u00e9 es el n\u00famero de 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,\u00a0<\/span><a title=\"Numero Reynolds\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/reynolds-number\/\"><span>Reynolds<\/span><\/a><span>\u00a0y Nusselt para este r\u00e9gimen de flujo (flujo turbulento forzado interno) dentro de la red de combustible rectangular (canal de combustible), luego calcule el\u00a0<\/span><strong><span>coeficiente de transferencia de calor<\/span><\/strong><span>\u00a0y finalmente la\u00a0<\/span><strong><span>temperatura de la superficie<\/span><\/strong><span>\u00a0del\u00a0<strong>revestimiento<\/strong>\u00a0,\u00a0<\/span><strong><span>T\u00a0<\/span><sub><span>Zr, 1<\/span><\/sub><\/strong><span>\u00a0.<\/span><\/p>\n<p><span>Para calcular la\u00a0<\/span><strong><span>temperatura de la superficie<\/span><\/strong><span>\u00a0del\u00a0<strong>revestimiento<\/strong>\u00a0, tenemos que calcular el n\u00famero de\u00a0<\/span><strong><span>Prandtl<\/span><\/strong><span>\u00a0,\u00a0<\/span><strong><span>Reynolds<\/span><\/strong><span>\u00a0y\u00a0<\/span><strong><span>Nusselt<\/span><\/strong><span>\u00a0, porque la transferencia de calor para este r\u00e9gimen de flujo puede describirse mediante la\u00a0<\/span><strong><span>ecuaci\u00f3n de Dittus-Boelter<\/span><\/strong><span>\u00a0, que es:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Dittus-Boelter-Equation-Formula.png\"><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\" alt=\"Ecuaci\u00f3n 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\" \/><\/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>C\u00e1lculo del n\u00famero de Prandtl<\/span><\/h2>\n<p><span>Para calcular el\u00a0<\/span><a title=\"\u00bfQu\u00e9 es el n\u00famero de Prandtl?\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-prandtl-number\/\"><span>n\u00famero de Prandtl<\/span><\/a><span>\u00a0, tenemos que saber:<\/span><\/p>\n<ul>\n<li><span>La conductividad t\u00e9rmica del agua saturada a 300 \u00b0 C es:\u00a0<\/span><strong><span>k\u00a0<\/span><\/strong><strong><sub><span>H2O<\/span><\/sub><\/strong><strong><span>\u00a0= 0.545 W \/ mK<\/span><\/strong><\/li>\n<li><span>La viscosidad din\u00e1mica del agua saturada a 300 \u00b0 C es:\u00a0<\/span><strong><span>\u03bc = 0.0000859 Ns \/ m\u00a0<\/span><\/strong><strong><sup><span>2<\/span><\/sup><\/strong><\/li>\n<li><span>el\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/first-law-of-thermodynamics\/heat-capacity\/\"><strong><span>calor espec\u00edfico<\/span><\/strong><\/a><span>\u00a0es:\u00a0<\/span><strong><span>c\u00a0<\/span><\/strong><strong><sub><span>p<\/span><\/sub><\/strong><strong><span>\u00a0= 5,65 kJ \/ kg.K<\/span><\/strong><\/li>\n<\/ul>\n<p><span>Tenga en cuenta que todos estos par\u00e1metros difieren significativamente para el agua a 300 \u00b0 C de aquellos a 20 \u00b0 C.\u00a0El n\u00famero de Prandtl para\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-of-water\/\"><span>agua<\/span><\/a><span>\u00a0a 20 \u00b0 C es de alrededor de\u00a0<\/span><strong><span>6.91.\u00a0<\/span><\/strong><span>El n\u00famero de Prandtl para el refrigerante del reactor a 300 \u00b0 C es entonces:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/prandtl-number-example.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-20411 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/prandtl-number-example.png\" alt=\"n\u00famero prandtl - ejemplo\" width=\"469\" height=\"80\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/prandtl-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-spacer\"><\/div>\n<h2><span>C\u00e1lculo del n\u00famero de Reynolds.<\/span><\/h2>\n<p><span>Para calcular el n\u00famero de Reynolds, tenemos que saber:<\/span><\/p>\n<ul>\n<li><span>El di\u00e1metro exterior del revestimiento es:\u00a0<\/span><strong><span>d = 2 xr\u00a0<\/span><sub><span>Zr, 1<\/span><\/sub><span>\u00a0= 9,3 mm<\/span><\/strong><span>\u00a0(para calcular el di\u00e1metro hidr\u00e1ulico)<\/span><\/li>\n<li><span>El paso de los pasadores de combustible es:\u00a0<\/span><strong><span>p = 13 mm<\/span><\/strong><span>\u00a0\u00a0(para calcular el di\u00e1metro hidr\u00e1ulico)<\/span><\/li>\n<li><span>La viscosidad din\u00e1mica del agua saturada a 300 \u00b0 C es:\u00a0<\/span><strong><span>\u03bc = 0.0000859 Ns \/ m\u00a0<\/span><\/strong><strong><sup><span>2<\/span><\/sup><\/strong><\/li>\n<li><span>la densidad del fluido es:\u00a0<\/span><strong><span>\u03c1 = 714 kg \/ m\u00a0<\/span><\/strong><strong><sup><span>3<\/span><\/sup><\/strong><\/li>\n<\/ul>\n<p><strong><span>El di\u00e1metro hidr\u00e1ulico, D\u00a0<\/span><\/strong><strong><sub><span>h<\/span><\/sub><\/strong><span>\u00a0, es un t\u00e9rmino com\u00fanmente utilizado cuando se maneja el flujo en\u00a0<\/span><strong><span>tubos y canales no circulares<\/span><\/strong><span>\u00a0.\u00a0El\u00a0<\/span><strong><span>di\u00e1metro hidr\u00e1ulico del canal de combustible<\/span><\/strong><span>\u00a0,\u00a0<\/span><em><span>D\u00a0<\/span><\/em><em><sub><span>h<\/span><\/sub><\/em><span>\u00a0, es igual a 13,85 mm.<\/span><\/p>\n<p><span>Ver tambi\u00e9n:\u00a0<\/span><a title=\"Di\u00e1metro hidr\u00e1ulico\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/internal-flow\/hydraulic-diameter-2\/\"><span>di\u00e1metro hidr\u00e1ulico<\/span><\/a><\/p>\n<p><span>El\u00a0<\/span><strong><span>n\u00famero de Reynolds<\/span><\/strong><span>\u00a0dentro del canal de combustible es igual a:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/reynolds-number-example.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-20412 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/reynolds-number-example.png\" alt=\"n\u00famero de reynolds - ejemplo\" width=\"593\" height=\"78\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/reynolds-number-example.png\" \/><\/a><\/p>\n<p><span>Esto satisface completamente las\u00a0<\/span><a title=\"Flujo turbulento\" href=\"https:\/\/www.thermal-engineering.org\/es\/que-es-el-flujo-turbulento-definicion\/\"><strong><span>condiciones turbulentas<\/span><\/strong><\/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 del n\u00famero de Nusselt usando la ecuaci\u00f3n de Dittus-Boelter<\/span><\/h2>\n<p><span>Para un flujo turbulento completamente desarrollado (hidrodin\u00e1micamente y t\u00e9rmicamente) en un tubo circular liso, el\u00a0<\/span><strong><span>n\u00famero<\/span><\/strong><span>\u00a0local de\u00a0<strong>Nusselt<\/strong>\u00a0se puede obtener de la conocida\u00a0<\/span><strong><span>ecuaci\u00f3n Dittus ?? Boelter<\/span><\/strong><span>\u00a0.<\/span><\/p>\n<p><span>Para calcular el\u00a0<\/span><strong><span>n\u00famero de Nusselt<\/span><\/strong><span>\u00a0, tenemos que saber:<\/span><\/p>\n<ul>\n<li><span>el\u00a0<\/span><a title=\"Numero Reynolds\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/reynolds-number\/\"><span>n\u00famero de Reynolds<\/span><\/a><span>\u00a0, que es\u00a0<\/span><strong><span>Re\u00a0<\/span><sub><span>Dh<\/span><\/sub><span>\u00a0= 575600<\/span><\/strong><\/li>\n<li><span>el\u00a0<\/span><a title=\"\u00bfQu\u00e9 es el n\u00famero de Prandtl?\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/heat-transfer\/introduction-to-heat-transfer\/characteristic-numbers\/what-is-prandtl-number\/\"><span>n\u00famero de Prandtl<\/span><\/a><span>\u00a0, que es\u00a0<\/span><strong><span>Pr = 0.89<\/span><\/strong><\/li>\n<\/ul>\n<p><span>El\u00a0<\/span><strong><span>n\u00famero de Nusselt<\/span><\/strong><span>\u00a0para la convecci\u00f3n forzada dentro del canal de combustible es 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 - ejemplo\" 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-spacer\"><\/div>\n<h2><span>C\u00e1lculo del coeficiente de transferencia de calor y la temperatura de la superficie del revestimiento, T\u00a0<\/span><sub><span>Zr, 1<\/span><\/sub><\/h2>\n<p><span>El conocimiento detallado de la geometr\u00eda, los par\u00e1metros del fluido, el radio exterior del revestimiento, la tasa de calor lineal, el coeficiente de transferencia de calor por convecci\u00f3n nos permite calcular la diferencia de temperatura\u00a0<\/span><strong><span>\u2206T<\/span><\/strong><span>\u00a0entre el refrigerante (T\u00a0<\/span><sub><span>volumen<\/span><\/sub><span>\u00a0) y la superficie del revestimiento (T\u00a0<\/span><sub><span>Zr, 1<\/span><\/sub><span>\u00a0).<\/span><\/p>\n<p><span>Para calcular la temperatura de la superficie del revestimiento, debemos saber:<\/span><\/p>\n<ul>\n<li><span>El di\u00e1metro exterior del revestimiento es: d = 2 x\u00a0<\/span><strong><span>r\u00a0<\/span><\/strong><strong><sub><span>Zr, 1<\/span><\/sub><\/strong><strong><span>\u00a0= 9,3 mm<\/span><\/strong><\/li>\n<li><span>el n\u00famero de Nusselt, que es\u00a0<\/span><strong><span>Nu\u00a0<\/span><\/strong><strong><sub><span>Dh<\/span><\/sub><\/strong><strong><span>\u00a0= 890<\/span><\/strong><\/li>\n<li><span>El di\u00e1metro hidr\u00e1ulico del canal de combustible es:\u00a0<\/span><strong><em><span>D\u00a0<\/span><\/em><\/strong><strong><em><sub><span>h<\/span><\/sub><\/em><\/strong><strong><span>\u00a0= 13,85 mm<\/span><\/strong><\/li>\n<li><span>La conductividad t\u00e9rmica del refrigerante del reactor (300 \u00b0 C) es:\u00a0<\/span><strong><span>k\u00a0<\/span><\/strong><strong><sub><span>H2O<\/span><\/sub><\/strong><strong><span>\u00a0= 0.545 W \/ mK<\/span><\/strong><\/li>\n<li><span>La temperatura total del refrigerante del reactor en esta coordenada axial es:\u00a0<\/span><strong><span>T\u00a0<\/span><\/strong><strong><sub><span>mayor<\/span><\/sub><\/strong><strong><span>\u00a0= 296 \u00b0 C<\/span><\/strong><\/li>\n<li><span>La tasa de calor lineal del combustible es:\u00a0<\/span><strong><span>q\u00a0<\/span><\/strong><strong><sub><span>L<\/span><\/sub><\/strong><strong><span>\u00a0= 300 W \/ cm<\/span><\/strong><span>\u00a0(F\u00a0<\/span><sub><span>Q<\/span><\/sub><span>\u00a0\u2248 2.0)<\/span><\/li>\n<\/ul>\n<p><span>El coeficiente de transferencia de calor por convecci\u00f3n,\u00a0<\/span><strong><span>h<\/span><\/strong><span>\u00a0, viene dado directamente por la definici\u00f3n del n\u00famero de Nusselt:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/convective-heat-transfer-coefficient-example.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-20410 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/convective-heat-transfer-coefficient-example.png\" alt=\"coeficiente de transferencia de calor convectivo - ejemplo\" width=\"619\" height=\"92\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/convective-heat-transfer-coefficient-example.png\" \/><\/a><\/p>\n<p><span>Finalmente, podemos calcular la temperatura de la superficie del revestimiento (T\u00a0<\/span><sub><span>Zr, 1<\/span><\/sub><span>\u00a0) simplemente usando la\u00a0<\/span><strong><span>Ley de Enfriamiento de Newton<\/span><\/strong><span>\u00a0:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Newton-law-of-cooling-example.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-20408 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Newton-law-of-cooling-example.png\" alt=\"Ley de enfriamiento de Newton - ejemplo\" width=\"377\" height=\"369\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Newton-law-of-cooling-example.png\" \/><\/a><\/p>\n<p><span>Para los PWR en funcionamiento normal, hay un\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-steam-what-is-steam\/saturated-and-subcooled-liquid\/\"><span>agua l\u00edquida comprimida<\/span><\/a><span>\u00a0dentro del n\u00facleo del reactor, bucles y generadores de vapor.\u00a0La presi\u00f3n se mantiene a aproximadamente\u00a0<\/span><strong><span>16MPa<\/span><\/strong><span>\u00a0.\u00a0A esta presi\u00f3n, el agua hierve a aproximadamente\u00a0<\/span><strong><span>350 \u00b0 C<\/span><\/strong><span>\u00a0(662 \u00b0 F).\u00a0Como se puede ver, la temperatura de la superficie T\u00a0<\/span><sub><span>Zr, 1<\/span><\/sub><span>\u00a0= 325 \u00b0 C garantiza que ni siquiera se produce una ebullici\u00f3n subenfriada.\u00a0Tenga en cuenta que, la ebullici\u00f3n subenfriada requiere T\u00a0<\/span><sub><span>Zr, 1<\/span><\/sub><span>\u00a0= T\u00a0<\/span><sub><span>sat<\/span><\/sub><span>\u00a0.\u00a0Dado que las temperaturas de entrada del agua suelen ser de unos\u00a0<\/span><strong><span>290 \u00b0 C<\/span><\/strong><span>(554 \u00b0 F), es obvio que este ejemplo corresponde a la parte inferior del n\u00facleo.\u00a0A elevaciones m\u00e1s altas del n\u00facleo, la temperatura aparente puede alcanzar hasta 330 \u00b0 C.\u00a0La diferencia de temperatura de 29 \u00b0 C hace que se produzca la ebullici\u00f3n subenfriada (330 \u00b0 C + 29 \u00b0 C&gt; 350 \u00b0 C).\u00a0Por otro lado, la\u00a0<\/span><strong><span>ebullici\u00f3n de nucleados<\/span><\/strong><span>\u00a0en la superficie altera efectivamente la capa estancada y, por lo tanto, la ebullici\u00f3n de nucleados aumenta significativamente la capacidad de una superficie para transferir\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/what-is-energy-physics\/internal-energy-thermal-energy\/\"><span>energ\u00eda t\u00e9rmica<\/span><\/a><span>\u00a0al fluido a granel.\u00a0Como resultado, el coeficiente de transferencia de calor por convecci\u00f3n aumenta significativamente y, por lo tanto, a elevaciones m\u00e1s altas, la diferencia de temperatura (T\u00a0<\/span><sub><span>Zr, 1<\/span><\/sub><span>\u00a0&#8211; T a\u00a0<\/span><sub><span>granel<\/span><\/sub><span>\u00a0) disminuye significativamente.<\/span><\/p>\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 art\u00edculo se basa en la traducci\u00f3n autom\u00e1tica del art\u00edculo original en ingl\u00e9s. Para m\u00e1s informaci\u00f3n vea el art\u00edculo en ingl\u00e9s. Puedes ayudarnos. Si desea corregir la traducci\u00f3n, env\u00edela a: translations@nuclear-power.com o complete el formulario de traducci\u00f3n en l\u00ednea. Agradecemos su ayuda, actualizaremos la traducci\u00f3n lo antes posible. Gracias.<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Este ejemplo muestra c\u00f3mo calcular la transferencia de calor por convecci\u00f3n.\u00a0C\u00e1lculo del coeficiente de transferencia de calor y la temperatura de la superficie del revestimiento.\u00a0Ingenieria termal Ejemplo &#8211; Convecci\u00f3n &#8211; Temperatura de la superficie del revestimiento Ejemplo &#8211; Convecci\u00f3n &#8211; Problema con la soluci\u00f3n\u00a0 El revestimiento\u00a0es la capa externa de las barras de combustible, que &#8230; <a title=\"\u00bfQu\u00e9 es un ejemplo de convecci\u00f3n? Problema con la soluci\u00f3n: definici\u00f3n\" class=\"read-more\" href=\"https:\/\/www.thermal-engineering.org\/es\/que-es-un-ejemplo-de-conveccion-problema-con-la-solucion-definicion\/\" aria-label=\"M\u00e1s en \u00bfQu\u00e9 es un ejemplo de convecci\u00f3n? Problema con la soluci\u00f3n: definici\u00f3n\">Leer m\u00e1s<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[16],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v15.4 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>\u00bfQu\u00e9 es un ejemplo de convecci\u00f3n? Problema con la soluci\u00f3n: definici\u00f3n<\/title>\n<meta name=\"description\" content=\"Este ejemplo muestra c\u00f3mo calcular la transferencia de calor por convecci\u00f3n. C\u00e1lculo del coeficiente de transferencia de calor y la temperatura de la superficie del revestimiento. 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