Theoretical analysis of the oscillating circular piston positive displacement flowmeter: II numerical solution of equations of motion and comparison with experimental data

In the first part of this paper, Morton et al. [1], we identified the forces and equations required to model the motion of the oscillating piston flowmeter. In this paper we discuss the method of solution, and the computational procedure for modelling the dynamic behaviour of the meter. We have, then, compared the model results with experimental data for variation in: angular velocity, vertical movement and pressure losses. We consider the agreement for variation in the following parameters: flow rate, piston mass, surface coating, lubrication holes, slots in piston skirt, length of up- and downstream pipe work, fluid viscosity and fluid density. We also compare the theory with data from two other sizes of meter. The predictions from the model are generally very accurate, although there is still potential to refine the model and increase further our understanding of the forces which contribute to the motion.