锥形内肋管传热与流阻性能的数值模拟

numerical simulation on heat transfer and flow resistance characteristics of conical ribbed tube

中文关键词: 换热管  强化传热  数值模拟  综合传热因子

英文关键词: heat transfer tube  heat transfer enhancement  numerical simulation  overall heat transfer factor

中文摘要:

      根据纵向涡强化传热技术提出了新型的强化换热管——锥形内肋管,运用数值模拟方法,研究了新型强化换热管结构参数锥底宽度a、导程P、肋深e和Re数对Nu、沿程阻力系数f及传热综合因子η的影响。结果表明：换热管内壁面边缘处产生了较多的微小涡流,有效破坏了流动边界层,强化了传热。在充分湍流的条件下,流体Re越小、e越小,其综合传热性能越强。当Re<15 000时,a对η的影响要大于P；在过渡点后, P对η影响较大。通过综合传热性能分析,给出了适合不同Re区间的锥形内肋优化参数。

英文摘要:

      A new kind of enhanced heat transfer tube named as cone-ribbed tube is developed in this paper based on the heat transfer enhancement technology by longitudinal vortex. The numerical simulation method was used to investigate the influence of some structural parameters such as conical bottom width, lead length, rib depth on Nu, resistance coefficients f and heat transfer efficiency index of the heat transfer process at different Reynolds number. The results show that many tiny vortices appear near the wall of conical rib and effectively enhance the heat transfer process by disturbing the boundary layer flow. At the fully turbulent flow condition, the smaller the Reynolds number and the rib depth are, the stronger is the overall heat transfer performance. When Re is less than 15000, the impact of the conical bottom width on overall heat transfer factor is greater than that of lead length; after the transition point, the impact of lead depth on the overall heat transfer factor is greater than that of the conical bottom width. By comprehensively analyzing the heat performance, the optimized structural parameters of conical rib are proposed to fit corresponding flows at different Reynolds numbers.