In order to make sure what factors have an effect on condensation, a mathematical model has been established for the discharging process of a pneumatic system using the fluid grid theory, an analytic equation has been derived to determine the maximum humidity of air during discharging of pneumatic system, and an analytic equation has been established as the first necessary condition for the determination of internal condensation in a pneumatic system. Flowing air may produce water droplets in a pneumatic system when the system satisfies the first necessary condition. An analytic equation has been developed as the second necessary condition for determination of internal condensation in a pneumatic system by introducing stroke and establishing an analytic equation for the stroke. The water droplets produced by satisfaction of the first necessary condition form drops of water inside the system when the system satisfies the second necessary condition. Internal condensation does not occur when the system does not satisfy the first necessary condition, and internal condensation occurs only when the system satisfies both conditions at the same time. The experimental results indicate that the points of internal condensation, external condensation and no condensation exhibit a regular distribution on the plane formed by the dimensionless volume of the discharging pipe and the average velocity of air, and the plane can then be divided into regions, providing a graphic discrimination method for determination of condensation in a pneumatic system.
Two-dimensional homogeneous and heterogeneous detonation wave propagation
