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Simplified and approximated correlations of heat transfer effectiveness for steam condenser

Laskowski R. M., Lewandowski J.

Journal of Power Technologies

2012

Vol. 92, nr 4

258--265

This paper presents two simplified and approximated relations of heat transfer effectivneness for steam condenser. The proposed relations of heat transfer effectivneness are a function of the measured and reference parameters. Correctness of relations were verified on the basis of data from the characteristics and measured data for the 200 MW steam condenser. A comparison of the outlet cooling water temperature calculated from the proposed relations and Beckman formula were performed. Formula proposed by Beckman for steam condenser of heat transfer effectivneness, in simplified form, is a function of saturation temperature, mass flow rate of cooling water and the reference parameter. It contains two constant exponents, which must be determined on the basis of the measured data. To assess the accuracy of the correlations the average value and standard deviation were used. The proposed correlations have simpler forms, but are slightly less accurate compared to the Beckman correlation.

Numerical simulation of heat transfer and two-phase flow in a novel heat pipe cold plate

Ma Z., Yao S.

Archives of Thermodynamics

2009

Vol. 30, no. 1

45-62

To solve high heat flux cooling problems in case of modern electronic appliances, a novel heat pipe cold plate is designed and developed. The heat pipe cold plate is uniquely-different from normal thermosyphons, in which the acetone-aluminum heat pipe construction is composed of eight vertical heat pipe branches with their upper ends and lower ends connected with each other by two horizontal heat pipe branches, respectively, which make the working vapour and liquid flow smooth within the internal flow space of the heat pipe cold plate. In this paper, based on previous experimental and theoretical studies, a mathematical model for numerical simulations of the vapour-liquid two-phase flow and heat transfer phenomena in the heat pipe cold plate is presented. Two-fluid-model is employed to describe flow characteristics and phase interaction between vapour and liquid phases. Differential equations are solved by finite volume method and IPSA algorithm is employed to consider the vapour-liquid coupling effect. Effects of the total heating power and the cooling water flow rate on wall temperature distribution and two-phase flow heat transfer characteristics are numerically simulated. Computation results well agree with experimental results. The novel heat pipe cold plate possesses excellent heat transfer characteristics and temperature uniformity performance; it can provide a much better cooling solution for multi-heat-source and high heat-flux cooling problems than forced-convection cooling techniques. Also, numerical solution established and realized in this paper can be used as a reference.