螺旋管内传热与流动性能的场协同分析

摘要

采用数值模拟的方法,分析了螺旋管内流体速度场和温度场的分布规律,研究了曲率和无量纲螺距对管内流体传热和流动性能的影响,以性能评价指标PEC(Performance Evaluation Criteria)为标准评价强化传热综合性能,并运用场协同理论对此进行了分析.结果表明:螺旋管内流体受二次流的影响,随着转角的增大,最大速度逐渐靠近外侧壁面,热量逐渐从管壁传递到管内核心区域;在相同雷诺数下,管内努塞尔数、摩擦系数和PEC均随曲率的增大而增大,而无量纲螺距对螺旋管传热和流动性能的影响则可以忽略不计;场协同理论可以很好地解释螺旋管结构参数对管内传热和流动性能的影响规律.%Numerically simulating the helically-coiled tubes were carried out to analyze the distribution of both velocity and temperature fields and the effect of both curvature and dimensionless pitch on heat transfer and flow performance and then, having it evaluated by the field synergy theory, including having the value of PEC (performance evaluation criteria) taken to assess the comprehensive heat transfer performance.The results show that, the secondary flow influences the fluid within the helically-coiled tube and with the increase of angle of rotation, the maximum velocity closes to the outer wall and the heat gradually transfers from the inner boundary layer to the core region of the fluid;as for the same Reynolds number,the Nusselt number and fric-tion coefficient and PEC rise with the increase of curvature and the influence of dimensionless pitch on the heat transfer and flow performance can be negligible.The field synergy theory can express the effect of the structur-al parameters of helically-coiled tube on the heat transfer and flow performance.