The influence of microjet array area ratio on heat transfer in the compact heat exchanger

Abstract

The paper describes the comprehensive study on the effect of microjet array geometrical parameters on the heat transfer enhancement in the modular heat exchanger. The conducted experimental study provides an experimental database on single phase submerged microjet heat transfer. The Wilson plot method was applied to determine the heat transfer coefficients in the laminar and transition flow regimes of a liquid-to-liquid heat exchanger. The heat exchanger was capable of exchanging 296 W of thermal energy at LMTD of 44 K. The obtained heat transfer coefficient reaches over 24,000 W/m2 K.Average Nusselt number predictions of the Wen and Jang (2003) correlation were in best agreement with the experimentally determined average Nusselt numbers. In the whole tested flow range, Nusselt numbers were not well correlated by any of the correlations from the literature. The experimentally determined Nusselt numbers were significantly lower than expected, due to limited applicability of given literature correlations.The author also proposed own experimental correlation for jet impingement heat transfer coefficient, predicting the experimental results within 30%.