Numerical simulation of SV type direct contact heat exchangers with different thicknesses

In order to enhance the heat transfer efficiency of direct contact heat exchangers, numerical simulation methods have been employed to investigate three different thicknesses of SV hybrid elements. An experimental platform for direct contact heat transfer was established, utilizing THERMINOL62 synthetic heat transfer oil and R141b refrigerant as the working fluids. The maximum relative error between the experimental heat transfer results and numerical simulation results was within 3%, indicating the accuracy of the numerical simulation in reflecting the direct contact heat transfer process. The results showed that the heat transfer effectiveness of the heat exchanger with a thickness of 3 mm (a heat exchanger equipped with SV hybrid elements with a thickness value of 3 mm) was superior, manifested by a higher outlet temperature of the gaseous working fluid. Compared to heat exchangers with thicknesses of 2 mm and 4 mm, the separation intensity decreased to 0.03, representing reductions of 62.5% and 25% respectively. Turbulence intensity values were relatively high, with some exceeding 10%, reaching a peak of 19.57%. Compared to heat exchangers with thicknesses of 2 mm and 4 mm, the volumetric heat transfer coefficients increased by 8.9% and 3.7% respectively. The maximum pressure drop of heat exchangers with a thickness of 3 mm and 4 mm increased by 2.91% and 3.0% compared to those with a thickness of 2 mm. This work shows that appropriately increasing the thickness of SV hybrid elements (3 mm) can afford better heat transfer efficiency without causing excessive pressure drop.