Numerical Analysis On The Fluctuation Flow Inside Roots Blower

The new revised formula and computing method of Roots blower were put forward in this article. Result of the revised formula is better than the experience formula in common use at present. The error between computing result and the experiment result is less than 5 percent.The forecast about the transient exhaust flux at different turning angle of air cooling blower's impeller is achieved from writing program of FORTRAN language. The pulsation of the higher exhaust pressure is bigger through comparing fluctuation curve under difference working condition. The bigger exhaust flux of the higher pressure is smaller than the lower one.Appling the PISO algorithm in CFD software, non-conformal interface at the rotor-stator coupled area in blower and wall function in the computation velocity and temperature at near wall, spring-based smoothing method and local remeshing method in the rotation field, the flow field of Roots blower was computed. Cubage efficiency achieved by numerical analysis and experiment is consistent. The exhaust flux curve was received by using UDF in the CFD software accords with the theory curve. In addition, the flow characteristic in the Roots blower is analyzed.The higher pressure Roots blower with adverse current and refrigerant was simulated with the same method above. The flow under two different pressure pulsation and different time was analyzed. Compared with the air cooling blower, the higher pressure adverse current blower eliminates the revised impact of the vent, the exhaust fluctuation is smaller, average amplitude reduces about 80 percent.The numerical simulation method of the article can be used as kind of reliable analysis tool, to review if the flow condition of the Roots blower reaches the design require or not.