We are going to have a SP&E seminar on "Effect of ambient heat-in-leak on a three-fluid cryogenic heat exchanger with two thermal communications" on Thursday 12th September 2013, given by Dr V.KRISHNA from PES Institute of Technology (PESIT), Bangalore, India. 

Date & Time:  2:00-3:00 PM, 12th September 2013, Thursday

Venue:  PG Suite 468, James Watt Building South

Tea/coffee before the start.

All welcome

 

Abstract:

A three-fluid cryogenic heat exchanger, involving two thermal interactions, is investigated for the effect of ambient heat-in-leak, using the analytical method and FEM for four different flow arrangements. The three fluids are referred to as hot, cold and the intermediate fluids. Several non-dimensional parameters inclusive of one to account for the ambient heat-in-leak are defined to present the results. The set of non-dimensional governing equations are solved analytically by the method of decoupling transformations. The governing equations are also solved by FEM using the Galerkin’s method. An exponentially distributed grid is used for the FEM analysis. Validation is carried out by comparing the present methodology with those published in the literature for limited parameters. The excellent match between the two validates the solution methodologies used. The effect of ambient heat-in-leak is studied for its effect on the fluid temperature profiles for the different flow arrangements. Ambient heat-in-leak is found to increase the fluid temperatures in all flow arrangements. For the values of the non-dimensional parameters chosen, the flow arrangement involving the hot fluid flowing counter to the other two fluids, is found to have the lowest hot fluid exit temperatures, indicating that this is the best arrangement for the cooling of the hot fluid.  Further, the effect of ambient heat-in-leak and varying non-dimensional parameters are studied for their effect on the hot fluid effectiveness for this flow arrangement. In most cryogenic applications, heat in leak from the ambient is a significant factor for the degradation in the performance of heat exchangers. The present analysis takes this factor into account. The FEM technique is found to be a very versatile tool, which can account for real time situations with relative ease and arrive at accurate results. The results presented give valuable inputs towards better understanding of the design and analysis of this class of cryogenic heat exchangers.

Biography

Dr V.KRISHNA  is Associate Professor in Mechanical Engineering at P.E.S.I.T., Bangalore, India

First published: 13 August 2012

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