空调风机叶道内旋涡流动分析及进气口偏心的影响

本文采用CFD方法,详细分析了空调用多翼离心风机叶道中的气流分布以及进气口偏心的影响。研究表明,风机叶道内存在大范围的气流分离现象。在后盘附近,存在分离现象的叶道约占2/3,主要分布在蜗壳内侧;而在“前盘”附近,几乎所有叶道都存在分离现象。在“前盘”附近,蜗舌下方的叶道中气流几乎停滞,蜗舌下游叶道为回流和尾缘旋涡所充满,至临近蜗壳出口侧,前缘旋涡逐步形成、发展并融合尾缘旋涡,最后衰减、消失。风机进气口向蜗壳内侧偏置适当距离, “前盘”附近叶道旋涡分布范围明显减小。

ANALYSIS ON THE VORTICES FLOW IN THE BLADE PASSAGES OF THE FAN FOR AIR-CONDITIONER AND THE INFLUENCE OF THE ECCENTRIC FAN INLET

The vortices flow in the blade passages and the influence of the eccentric inlet of the multi-blade centrifugal fan for air-conditioner have been analyzed numerically by using commercial CFD code. Calculation results reveal the existence of massive separations in the blade passages. Near the back plate of the rotor, the separated flow at the leading edge on the blade suction surface occurs in about two thirds of the blade passages. While near the shroud side of the rotor, it occurs in almost all of the blade passages. The flow is nearly stagnated in the blade passages under the volute tongue, after that the blade passages are filled with the flow reversal and the vortex generated at the trailing edge. In the blade passages beside the fan outlet, the vortex generated at the leading edge is gradually developed, coalesced the vortex generated at the trailing edge, then decayed and disappear finally. Numerical results also indicate that the vortex flow will be weakened when the fan inlet is installed eccentric to the inner volute.