Laminar flow and heat transfer characteristics of jacketed vessel with triangular flow channels were numerically studied under hydrodynamically and thermally fully developed conditions. Constant heat flux at theheated...Laminar flow and heat transfer characteristics of jacketed vessel with triangular flow channels were numerically studied under hydrodynamically and thermally fully developed conditions. Constant heat flux at theheated wall was assumed. The numerical program code interms of vorticity, stream function, axial velocity com ponent and energy equations was written based on a finite volume method. Based on the numerical results, the flow and temperature field were given, and the effects of Dean and Prandtl numbers on flow and heat transfer were ex amined, and the correlations of flow resistance and mean Nusselt number were developed for the jacket. The results show that the structure of secondary flow is steady two vortices in the investigated range of dimensionless curvatureratio and Reynolds number. Two peaks of local Nusselt number increase significantly with Prandtl and Dean num ber increasing, but the local Nusselt numbers near two ends and at the center of the heated wall increase only slightly. The center and two ends of heated wall are the poor positions for heat transfer in the jacket. Compared with the outer half coil jacket at the same area of heated wall, curvature radius, Reynolds number and Prandtl number, e jacket of triangular flow chmnel has lower flow resistance and less mean Nusselt number.展开更多
自由液面的捕捉应用VOF法,气液两相流时均方程采用RNG湍流模型封闭,采用数值模拟的方法计算了6种工况下,三角形波浪底板消力池自由水跃的流体力学特性.采用有限体积法离散微分方程,速度与压力耦合求解使用了压力隐式算子分裂PISO(Pressu...自由液面的捕捉应用VOF法,气液两相流时均方程采用RNG湍流模型封闭,采用数值模拟的方法计算了6种工况下,三角形波浪底板消力池自由水跃的流体力学特性.采用有限体积法离散微分方程,速度与压力耦合求解使用了压力隐式算子分裂PISO(Pressure-Implicit with Splitting of Operators)算法.研究发现:波浪形底板表面附近有漩涡产生,漩涡沿顺时针方向旋转,漩涡的尺寸沿程逐渐减小;沿程横断面上的最大流速在不同工况下有相似的衰减规律;在闸门附近产生紊动耗散率和紊动动能最大值及最大变化梯度,随进口弗劳德数的增大紊动能和耗散率最大值也增大;理论消能率和实际消能率均随进口弗劳德数增大而增大.展开更多
基金Supported by the Speciai Pogram forLocal Universities Development of Central Finance of China （2050205）, the National Natural Science Foundation of China （21106086）, and the Program for Liaoning Excellent Talents in University （LJQ2012035）.
文摘Laminar flow and heat transfer characteristics of jacketed vessel with triangular flow channels were numerically studied under hydrodynamically and thermally fully developed conditions. Constant heat flux at theheated wall was assumed. The numerical program code interms of vorticity, stream function, axial velocity com ponent and energy equations was written based on a finite volume method. Based on the numerical results, the flow and temperature field were given, and the effects of Dean and Prandtl numbers on flow and heat transfer were ex amined, and the correlations of flow resistance and mean Nusselt number were developed for the jacket. The results show that the structure of secondary flow is steady two vortices in the investigated range of dimensionless curvatureratio and Reynolds number. Two peaks of local Nusselt number increase significantly with Prandtl and Dean num ber increasing, but the local Nusselt numbers near two ends and at the center of the heated wall increase only slightly. The center and two ends of heated wall are the poor positions for heat transfer in the jacket. Compared with the outer half coil jacket at the same area of heated wall, curvature radius, Reynolds number and Prandtl number, e jacket of triangular flow chmnel has lower flow resistance and less mean Nusselt number.
文摘自由液面的捕捉应用VOF法,气液两相流时均方程采用RNG湍流模型封闭,采用数值模拟的方法计算了6种工况下,三角形波浪底板消力池自由水跃的流体力学特性.采用有限体积法离散微分方程,速度与压力耦合求解使用了压力隐式算子分裂PISO(Pressure-Implicit with Splitting of Operators)算法.研究发现:波浪形底板表面附近有漩涡产生,漩涡沿顺时针方向旋转,漩涡的尺寸沿程逐渐减小;沿程横断面上的最大流速在不同工况下有相似的衰减规律;在闸门附近产生紊动耗散率和紊动动能最大值及最大变化梯度,随进口弗劳德数的增大紊动能和耗散率最大值也增大;理论消能率和实际消能率均随进口弗劳德数增大而增大.
