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| Numerical simulation and design method of hot air for porous pipe based on CFD |
| Wang Xinkun, Xu Wenbo, Zhao Kun, Li Junhong, Xu Ying |
(Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang, Jiangsu 212013, China) |
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Abstract To overcome the 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-εturbulent model and the SIMPLEC algorithm. By using the search principle of bisection algorithms, numeric heat transfer theory, hydrodynamics and back step method, a design method of hot air heating in 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 is 278 K, the coefficient of conducting heat of the boundary is 0.055, the temperatures on the other orifice on the porous pipe were almost the same, and the pressures had the pressure-drop of about 200 Pa. The results of design were a little higher than that of numerical simulated 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 uniformity for a porous pipe.
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Received: 18 March 2010
Published: 30 January 2011
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