Effect of ambient heat-in-leak on the performance of three-fluid cross-flow heat exchanger
International Journal of Numerical Methods for Heat & Fluid Flow
ISSN: 0961-5539
Article publication date: 28 September 2018
Issue publication date: 19 October 2018
Abstract
Purpose
Heat exchangers working in cryogenic temperature ranges are strongly affected by heat ingression from the ambient. This paper aims to investigate the effect of ambient heat-in-leak on the performance of a three-fluid cross-flow cryogenic heat exchanger.
Design/methodology/approach
The governing equations are derived for a three-fluid cross-flow cryogenic heat exchanger based on the conservation of energy principle. For given fluid inlet temperatures, the governing equations are solved using the finite element method to obtain exit temperatures of the three-fluid exchanger. The performance of the heat exchanger is determined using effectiveness-number of transfer units (e-NTU) method. In the present analysis, the amount of ambient heat-in-leak to the heat exchanger is accounted by two parameters Ht and Hb. The variation of the heat exchanger effectiveness due to ambient heat-in-leak is analyzed for various non-dimensional parameters defined to study the heat exchanger performance.
Findings
The effect of ambient heat in leak to the heat exchanger from the surrounding is to increase the dimensionless exit mean temperature of all three fluids. An increase in heat in leak parameter (Ht = Hb) value from 0 to 0.1 reduces hot fluid effectiveness by 32 per cent for an NTU value of 10.
Originality Value
The effect of heat-in-leak on a three-fluid cross-flow cryogenic heat exchanger is significant, but so far, no investigations are carried out. The results establish the efficacy of the method and throw light on important considerations involved in the design of such heat exchangers.
Keywords
Citation
K.H., J., Y.T., K., Venkataram, K. and Seetharamu, K.N. (2018), "Effect of ambient heat-in-leak on the performance of three-fluid cross-flow heat exchanger", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 28 No. 9, pp. 2012-2035. https://doi.org/10.1108/HFF-05-2017-0205
Publisher
:Emerald Publishing Limited
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