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对三角形螺旋夹套内流体的湍流流动及换热性能进行了模拟,得到了充分发展条件下恒定热流加热时釜内湍流流体的速度场,分析了雷诺数(Re)和无量纲曲率(κ)对流体阻力和换热性能的影响,并由模拟数据拟合出平均阻力系数及平均努赛尔数的关联式.结果表明,湍流流动中,夹套内流体的二次流动为稳定的二涡结构,随雷诺数增大,二次流强度和湍动能均增强.由于离心力的作用,外壁面的阻力系数远大于内壁面.换热面上局部努塞尔数的峰值出现在靠近二次涡中心位置的换热壁面处,换热面中心处的局部努塞尔数约为峰值的85%.随Re和κ增大,峰值处的局部努塞尔数值增大最明显,流体的平均努塞尔数及阻力系数均增大.在所模拟的范围内,三角形螺旋夹套的效率因子E>3.7,且随Re和κ增大,E逐渐增大.
The turbulent flow and heat transfer performance of the fluid in the triangular helical jacket were simulated. The velocity field of the turbulent fluid in the autoclave was obtained under the condition of fully developed heat flow. Reynolds number (Re) and dimensionless curvature (κ) On the fluid resistance and heat transfer performance, and by the simulation data to fit the average drag coefficient and the average Nusselt number of correlations.The results show that turbulent flow, the second flow of the fluid jacket is a stable two vortex As the Reynolds number increases, the secondary flow strength and turbulent kinetic energy are enhanced.Due to the centrifugal force, the drag coefficient of the outer wall is much larger than that of the inner wall.The peak value of the local Nusselt number on the heat exchange surface appears near the secondary vortex The local Nusselt number at the center of the heat exchange surface is about 85% of the peak value at the center of the heat exchange wall, and the local Nusselt number increases sharply with the increase of Re and κ, The number of sellers and the drag coefficient all increase.The efficiency factor of the triangular helical jacket is> 3.7 in the simulated range, and E increases with the increase of Re and κ.