Flow characteristic and trapping characteristics of cycloid rotor pump

To accurately calculating the flow rate of cycloid rotary pump, as well as to correctly understand its trapped oil phenomenon. Firstly, the instantaneous flow rate formula of cycloid rotary pump was established based on the method of swept area, and compared with the two present approximate formulas by an example. Secondly, based on the just established flow rate formula and the created trapped oil model in present literature, the trapped oil pressure of a single cavity near in the minimum volume position was simulated. It is pointed that for cycloid rotary pump by an example, the flow non-uniform coefficient is 6.45%, in contrast, the flow nonuniformity coefficient of external gear pump is 21.2%; Relative to the accurate results, the two present approximate errors of flow rates are 1.93% and 2.90%; and the present approximate error of flow non-uniform coefficient is 7.13%; when the minimum position angle is added by 0.5° or 1° or 2°, relative to discharge pressure of the pump, the corresponding maximum peak of trapped oil pressure is increased by 1.6% or 6.0% or 21.7%. The results indicate that the flow characteristics of cycloid rotary pump is better than external gear pump; the two present approximate errors of flow rate are little, but the present approximate error of flow nonuniform coefficient is higher; also there is a trapped oil phenomenon in cycloid rotary pump, but not obvious. © Zhenxing et al.; Licensee Bentham Open.