Experimental study on the flow and heat transfer performance of a catalyst-filled plate-fin heat exchanger for hydrogen liquefaction

Ortho-para hydrogen conversion (OPHC) is a crucial process in hydrogen liquefaction. To achieve continuous OPHC during the hydrogen liquefaction process, an experimental setup for the catalyst-filled plate-fin heat exchanger (CFPFHE) was established. The flow and heat transfer performance of the CFPFHE was systematically investigated under H₂ and N₂ conditions at room and low temperatures. Based on the experimental results, local resistance coefficients for the hot side (K_h) and cold side (K_c) channels were determined, revealing that K_h is independent of fluid type and pressure, whereas K_c varies with H₂ and N₂. Additionally, at room temperature, the hot side friction factor (f_h) is nearly two orders of magnitude higher than the cold side friction factor (f_c), indicating the strong impact of the catalyst layer on flow resistance. At low temperature, a modified resistance correlation for f_c is proposed, which can improve the prediction accuracy of f_c by 9.32 %. For the catalyst-filled channels (hot side), it was found that, as the Reynolds number (Re_h) increased, the heat transfer factor (j_h) and the thermal enhancement factor (TEF) initially increased and then decreased. The j_h reached a maximum value of 0.045 at Re_h = 180, and the TEF peaked at 0.0153 around Re_h = 241. Furthermore, correlations for j_h and f_h within the range of Re_h < 1400 were obtained. The results provide theoretical guidance for the design optimization of the CFPFHE, which is beneficial for reducing the energy consumption of the hydrogen liquefaction process.