The aim of the article is improvement of numerical cavitation models for simulation of an effect of cavitation stabilization of fluid mass flow. The methods of development of a new dynamic component for a numerical model of cavitation mass transfer is presented in the paper. Application of the new method resulted in a new dynamic component for numerical model of cavitation mass transfer, which takes into account fluid viscosity in Reley-Plesset equation. Relying on the methods being considered fundamentally new hydroautomatic devices such as cavitation mass flow stabilizers and flow dividers could be designed. The new dynamic component has become the basis for the new numerical model of cavitation mass transfer. The effect of cavitation stabilization of fluid mass flow was simulated by this dynamic component. The numerical model was verified by experimental researches of the effect of cavitation stabilization of fluid mass flow in a jet element "pipe-pipe". The results of simulation showed that the new numerical model of cavitation mass transfer can simulate the jet pipes with the difference between results of simulation and experiment not exceeding 2,5% and visualizing a cavitation zone more adequate.

The problems of braking and positioning of hydraulic actuators are an integral part of output speed control in hydro-pneumatic actuators. This article is focused on a hydraulic braking of driven elements of machines and mechanisms which is carried out by devices known as brake valves (counterbalance, load control, over-centre valves). Brake valves are used to exclude overrunning speed under passing loads when the external load direction coincides with the direction of movement (rotation) of the hydraulic actuator. They provide a constant pressure in pressure line and prevent cavitation. In this article the design and operation of brake valves are analyzed. The need for brake valves in hydraulic machines with hydraulic actuators under a passing load is proved. As a result of theoretical research a mathematical model of dynamics of hydraulic actuator with a brake valve has been developed. This model unlike others takes into account the design of main and control spools of the brake valve. The problem of logging-running unit braking is solved by the use of the hydraulic brake valve as a part of hydraulic logging system.