Sensitivity analysis of a louvered micro-channel evaporator

Abstract

Most of the reported optimizations of micro-channel evaporators focus on specific variables, their priority has not been revealed. In the present study, a numerical model for a louvered micro-channel evaporator is established. The operating patterns under different cases are first revealed. Then, sensitivity analysis of operational and structural parameters is analyzed; sensitivity coefficients are additionally revealed to enumerate the priority. The results indicate that the influence mechanism and sensibility of different operating factors are distinct. The log-mean temperature difference (LMTD) increases first and then decreases with the air speed while the overall heat transfer coefficient increases first and then decreases with the inlet dryness. In other cases, the LMTD, heat transfer rate, entropy generation, and overall heat transfer coefficient display positive or negative variation trends with the operating factors. On the whole, the air speed, initial air temperature, and mass flow rate of the refrigerant play positive roles while the cross-sectional size and inlet dryness play opposite roles in determining the heat transfer performance. Of which, the heat transfer rate is positively determined by the initial air temperature with the maximum value of 0.85 while negatively determined by the inlet dryness with the value of −0.23; the overall heat transfer coefficient is positively determined by the air speed with the value of 0.83 while negatively determined by the cross-sectional size with the maximum value of −0.41. The mass flow rate of the refrigerant makes no difference in determining the heat transfer performance.