Vol 1, No 2 (2014)

Modern rocket propulsion system is a dynamic system with a set of inter- connected links Modern controlled propulsion system, ensuring in the pro- cess of its operation on the aircraft receiving the given basic characteristics. Main propulsion controlled variable serving as controlled object is second mass flow of gases through the nozzle. Regulating influence area is man- aged throttle hydraulic adjusting the surface area of solid fuel combustion by draining the channel charge. Currently achieved level of development of computer technology allows to simulate the behavior of the object and its management systems. This helps improve the design quality and reduce de- bugging time hydroelectric generators.

The influence of fluid flow and pressure drop in the level of vibrations in continuous operation windows opening electrohydraulic amplifier (EHP). It is shown that the vibration level is determined by the speed of its flow in the windows of the EHP. At speeds greater than the critical value, its impact on the level of vibrations is negligible. Changes in the level of vibration signifi- cantly to the differential pressure of 2,94 MPa, with a further increase in its level of vibration is changed slightly. It is also shown that a high air content in the liquid leads to the formation of transonic flow of the working fluid with increased vibroaktivnosti hydraulic devices.

Modern cryostatting systems find important applications in power and space transportation systems. The cryostatting system is a closed hydraulic loop for the thermal management and control of thermal modes of supercon- ducting cable lines, cryogenic rocket and space units fuel tanks. The working medium is liquid nitrogen. One of the main components of such a system is the criorefrigirator. In the criorefrigirator compression scheme is used with following expansion of neon in the turboexpander, machine with gas-static bearings. Urgent task in the design phase is to determine the pressure fluc- tuations in the flow of the turbo expander and dynamic loading of the struc- ture. This paper presents the numerical simulation of unsteady gas-dynamic processes in the turbo expander radial turbine flow. Expansion turbine con- sists of mounted on the same shaft the radial turbine impeller and centrifugal compressor first stage, that also serves as a gas-dynamic brake. Gas is fed to the expander casing through two pipelines. Further, it is accelerated in the nozzle cascade and enters the turbine impeller blades. After expansion and reduction the temperature, the exhaust gas passes through the axial diffuser. Rotor speed is 25,200 rev / min. The geometry of the computational domain is developed in order to capture the main features of the flow in the working fluid cavity, including the geometry of fourteen working blades and eight vanes of the nozzle cascade. The computational domain is divided into three subregions: the casing of the nozzle cascade, rotor and exhaust part. The problem is solved with the use of so-called sliding surfaces which serve for transmitting the data from the rotor, where the calculation is carried out in a rotating coordinate system into the stator zone accounting an angular dis- placement and sub-grid interpolation. Time step chosen from the condition to ensure the angular displacement in one time step within a single cell of the computational grid. The instantaneous velocity, pressure, temperature and Mach number fields are obtained with calculations. Few points in the nozzle vane channel oblique zones are selected to fix pressure pulsations. The spectral analysis of the data reveal that the tonal component with blades passing frequency dominates the spectra of pressure pulsations, its ampli- tude is above 7000 Pa. Calculation of loading on nozzle blade gives the am- plitude of force 2 N and amplitude of momentum 0.03 N m