Numerical study and experimental validation on heat and water transfer through polymer membrane by applying a novel enhancement technique

摘要

In the present study, a three dimensional numerical simulation is performed to investigate the heat and water transfer enhancement in a polymer membrane humidifier with partially blocked channel. The experimental tests are also conducted for validation purposes. The thermal-hydraulic performance factor (JF) is introduced as the main parameter to evaluate the humidifier performance with considering pressure drop. The higher value of JF indicates the higher heat transfer with the lower pressure drop. When there are equal mass flow rates at both wet and dry sides, three ranges of flow rates are identified. At low flow rates (less than 4.4 mg/s), with and without considering pressure drop, the blocked humidifier shows weaker performance than the simple humidifier, so blocking is not recommended under any circumstances. At moderate flow rates (between 4.4 mg/s and 6.65 mg/ s), regardless of pressure drop, the performance of the blocked humidifier is better than that of the simple humidifier, and with considering the pressure drop, the blocked humidifier performs weaker. At high flow rates (greater than 6.65 mg/s), with and without considering pressure drop, the blocked humidifier performs better than the simple humidifier. The same trend holds for the case of constant dry side flow rate with the variable wet side flow rate.