Analysis, prediction and multi-response optimization of heat transfer characteristics of a three fluid heat exchanger using response surface methodology and desirability function approach

Highlights: • Effect of parameters on thermal performance of the TFHE has been studied. • Statistical RSM model is developed by Box-Behnken design and checked with ANOVA. • Sensitivity analysis is performed to identify and rank various critical parameters. • Multi-response optimization analysis using desirability function approach is used. -- Abstract: In the present study, an effort is made to evaluate the effect of four non-dimensional input parameters i.e. curvature ratio (δ), non-dimensional coil pitch (λ), tube side Reynolds number (Re_i) and outer annulus side Reynolds number (Re_o) on thermal performance of the Three Fluid Heat Exchanger (TFHE). Interaction between these input parameters and their influences on heat transfer characteristics of the TFHE i.e. entropy generation number, Ns and tube side Nusselt number, Nu are assessed by a statistical RSM model developed by Box–Behnken design approach. Adequacy of the model is checked by ANOVA analysis and capability of the developed model is tested towards effective prediction of the output responses. Sensitivity analysis is performed to identify and rank various critical parameters with respect to their order of importance. To assess the optimal levels of input variables, a multi-response optimization analysis is performed using desirability function approach for maximum heat transfer i.e. Nu and minimum irreversibility loss i.e. Ns in the TFHE. It is found that the minimum value of entropy generation number and maximum value tube side Nusselt number for the optimum performance of the TFHE are predicted as 0.0719 and 115.244, respectively with a composite desirability, D of 0.903077. Performance of TFHE is found to be enhanced by 33.73% of reduction in entropy generation number and 21.46% increment in tube side Nusselt number.