Abstract
Heat transfer performance of two-stream parallel-flow gas-to-gas micro-double-tubes-heat exchangers was investigated numerically. The flow passages of the micro- double-tubes-heat exchanger are a circular tube for hot passage and a concentric annular tube for cold passage. A circular tube of r= 50 μm and a concentric annular tube of r_1=51 μm and r_0=71 μm with an identical cross-sectional area were chosen and the selected length was 20mm, respectively. Then, the partition wall is assumed to be a stainless steel tube with 1 μm in thickness. Numerical methodology is based on the arbitrary-Langrangian-Eulerian method. Computations were performed for wide flow range to find the effects of capacity ratio on the heat transfer characteristics of gas-to-gas micro-double-tubes-heat exchangers. The results are presented in form of temperature contours, bulk temperature, total temperatures and heat flux variation along the length. Also, the effectiveness and the number of transfer units approach and the estimation of the heat exchange rate were discussed.
