Investigation for Optimal Thermo Hydraulic Performance of Regenerative Heat Exchangers

Abstract

Thermo-hydraulic performance of Regenerative Heat Exchangers depends on the type newlineof matrix used in the heat exchanger. Matrix acts as an additional resistance to the path newlineof fluid flow due to which there is considerable pressure drop across the regeneration. newlineAs a result, pumping power required to maintain the fluid flow through the regenerator newlineincreases. It is always desirable to have a geometry of matrix which provides minimum newlinepumping power required to maintain the fluid flow through the regenerator while newlinestoring maximum heat energy when the hot fluid is flowing through it. newlineIn order to investigate the thermo-hydraulic performance of regenerative heat newlineexchangers an experimental set-up has been developed. Three types of matrices newlinenamely wire-mesh, spherical ball and lenticular shaped have been used. Experiments newlinewere conducted in the range of Reynolds number 5,000-12,000, porosity 0.50-0.70 newlineand Prandtl number = 0.7. newlinePressure difference across the orifice meter/regenerator, temperature of the matrices, newlineair at inlet and outlet to the regenerator and ambient temperature were recorded. Using newlineexperimental data calculations for NPH/NTU, friction factor f and Colburn modulus j newlinewere carried out for three matrices namely wire mesh, spherical ball and lenticular. newlineThe results were plotted. It has been found that lenticular shaped matrix performed the newlinebest amongst spherical ball and wire mesh. Experimental results are in good agreement newlinewith the CFD results. Uncertainty analysis shows that uncertainty in the measurement newlineof parameters for thermo-hydraulic performance is 1.55%. newlineThe thesis consists of seven chapters. First chapter deals with Introduction while the newlinesecond chapter is devoted to literature review. Thermo-hydraulic analysis of newlineregenerative heat exchanger is presented in chapter 3. System development is newlinedescribed in chapter 4, whereas chapter-5 and chapter-6 explain the experimentation, newlineresults and discussion respectively. Conclusion is mentioned in chapter-7. newline