Estimación del coeficiente de transferencia de calor global a bajas presiones en un condensador helicoidal integrado a un transformador térmico
Estimation of the condensation heat transfer coefficient for steam water at low pressure in a coiled double tube condenser integrated to a heat transformer
O. Flores1, V. Velázquez1, M. Meza1, H. Horacio1, D. Juárez2 y J. A. Hernández2*
1 Posgrado en Ingeniería y Ciencias Aplicadas de la Universidad Autónoma del Estado de Morelos. Av. Universidad No. 1001, Col Chamilpa, CP. 62209, Cuernavaca, Morelos, México.
2 Centro de Investigación en Ingeniería y Ciencias Aplicadas (CIICAp), Universidad Autónoma del Estado de Morelos (UAEM). Av. Universidad No. 1001, Col Chamilpa, CP. 62209, Cuernavaca, Morelos, México. * Autor para la correspondencia. E-mail: alfredo@uaem.mx Tel. 52-777-329-70-84, Fax. 52-777-329-70-84.
]]>Recibido 17 de octubre de 2012
Aceptado 23 de marzo de 2013
Resumen
Se realizó un estudio experimental para calcular el coeficiente de transferencia de calor de condensación de vapor de agua en un condensador de doble tubo helicoidal. El vapor fluye por el tubo interno y por la sección anular fluye a contra corriente agua de enfriamiento. La presión de operación del condensador se encuentra dentro del intervalo de 4 a 9 kPa con un número de Reynolds de vapor entre 7200 y 23200. Los flujos másicos por unidad de área del agua de enfriamiento están en un intervalo de 450 a 850 kg/m2s. El coeficiente de transferencia de calor de condensación es calculado por dos métodos: el primero es en base al balance de energía y ecuaciones de transferencia de calor; en el segundo, se utilizó la técnica Wilson Plot. Los valores calculados del coeficiente de transferencia de calor de condensación muestran similitud entre ambos métodos. El intervalo de los coeficientes de condensación obtenidos es de 2200 W/(m2 °C) ≤ αcon≤ 5500 W/(m2 oC). Además, una correlación para la estimación del coeficiente de condensación en función del número de Re y Pr es propuesta.
Palabras clave: coeficientes de transferencia de calor, condensación, condensador helicoidal, Wilson Plot, transformador térmico.
Abstract
An experimental study was conducted to calculate the condensation heat transfer coefficient of steam water in a double helical tube condenser. The steam flows through the inner tube and the cooling water flows in counter flow in the annular section. The operating pressure of the condenser is ranging from 4 kPa to 9 kPa and the Reynolds number of steam is ranging from 7200 to 23200. The mass flux of the cooling water is ranging from 450 kg/m2s to 850 kg/m2s. The heat transfer coefficient is calculated by two methods: the first is based on energy balance and heat transfer equations, and the second by Wilson Plot method. The heat transfer coefficient results shows similarity between both methods and it is ranging from 2200 W/m2oC to 55500 Wrm2oC. Furthermore, we propose a correlation for the condensation heat transfer coefficient based on the Nusselt, Reynolds and Prandtl numbers.
]]> Keywords: heat transfer coefficient, steam, coiled condenser, Wilson Plot, heat transformer.
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