关键词: 耗散, 换热器, 局部特性, 螺旋折流板, 数值模拟

Abstract: Models of continuous helical baffles and quarter helical baffles heat exchangers are established. With large CFD analysis software FLUENT, the distribution characteristics of local flow field and temperature field of helical baffles heat exchangers are investigated through numerical simulation. And comprehensive performances of both heat exchangers are compared and studied with entransy dissipation. The results show：In the research of heat exchanger, the evaluation standard of entransy dissipation is consistent with that of comprehensive performances. When the flow of shell side is the same, the entransy dissipation value of continuous helical baffles heat exchanger is less than that of quarter helical baffles heat exchanger. The distribution characteristics of local flow field and temperature field of both heat exchangers present the same rules, in the central part of shell side, heat transfer coefficient of tubes is the highest. Along the radial direction, both helical flow and heat transfer coefficient of tubes first increase then decrease. Compared to continuous baffles, the discontinuity of baffles could enhance local heat transfer. Yet, when flow increases to an extent, the local heat transfer in the center will be weakened. The results provide theoretical basis for the improvement of structure forms of helical baffles.

Key words: entransy dissipation, heat exchangers, helical baffles, local characteristic, numerical simulation