基于CFD的多扎管热风数值模拟与设计方法

针对目前温室热风采暖效率较低的现状，提出将多孔管应用于温室热风采暖的设计方法．利用Pro／E软件完成多孔管造型，应用Fluent6．2软件并设置三维雷诺平均Navier—Stokes方程、RNG k-ε紊流模型和SIMPLEC算法对多孔管内部流场进行了数值模拟．采用二分法搜索原理、数值传热学理论、流体力学和逆递推法对多孔管热风采暖进行设计计算，并运用VB6．0软件对其进行编程计算，得到了多孔管滴灌器的流态指数为0．507，性能良好；当设定进、出口压力分别为10，0kPa，进、出口温度分别为300，278K，边界壁面传热系数为0．055时，多孔管各出风孔口温度值几乎不变，压力值沿多孔管产生压降，约为200Pa．设计方法所得结果比数值模拟结果略高，各出风孔口处压力值和温度值的设计曲线和模拟曲线趋势一致，且压力值和温度值的均匀系数均大于0．8，满足多孔管热风流动均匀性的要求．

Numerical simulation and design method of hot air for porous pipe based on CFD

To overcome tire condition that the lowly efficient use of hot air heating in greenhouse, a design method of hot air heating for a porous pipe in greenhouse was put forward. The model of a porous pipe was created by using the Pro/E, the computational fluid dynamics software Fluent 6.2 was adopted to simulate the porous pipe interior flow mechanism and performance by setting up the Reynolds averaged Navier- Stokes equations, the RNG k -ε turbulent model and the SIMPI,EC algorithm. By using the search principle of bisection algorithms, numeric heat transfer theory, hydrodynamtes and back step method, a design method of hot air heating ill a porous pipe was studied, meanwhile which was computed by making use of VB 6.0 computer language program. The results show that the flow index of emitter on the porous pipe is 0. 507, the performance is fine. When the inlet pressure is 10 kPa, the outlet pressure is 0 Pa, the inlet temperature is 300 K, the outlet temperature Js 278 K, the coefficient of conducting heat of the boundary is 0. 055, the temperatures on the other orifice on the porous pipe were ahnost the same, anti the pressures had the pressure-drop of about 200 Pa. The results of design were a little higher than that of numerical simulaled ones, but the curves agreed with the pressure and temperature. Both the pressure and temperature uniformity coefficients were larger than 0. 8, which satisfied the need of hot air flow unitormity for a porous pipe.