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In this paper we make a comparison between the most common balancing systems used in heavy duty machine tools and especially in CNC type ones. We introduce the systems with reducing valves, pumps with pressure regulator and the systems with accumulators assembled in closed circuit. For the latter we present calculation models used during operation under adiabatic transformations (operating times of seconds) or under isothermal transformations (operating times of minutes). There are also presented applications of these models for a gantry type milling machine and an AF type machine.

Pressure regulators have a great impact on the runtime and energy savings of supersonic wind tunnels. In order to investigate this impact quantitatively the theoretical isentropic (ideal) equations for the supersonic wind tunnel flow were compared with viscous CFD computations. The theoretical model was extended include the flow from the outflow from the pressure vessel up to the wind tunnel. This theoretical model was solved with and without pressure regulation valve using a Runge-Kutta method. The differences in runtime and energy consumption for both configurations with and without pressure regulator as well as the derivation of the analytical model and the numerical solution are presented in detail in this paper.

In this paper an attempt has been reported to bring out the development and testing features of a laboratory scale induction system suited to bottled (fixed composition) PG powered IC engine. A four stroke, single cylinder, spark ignited engine was tested with a bottled PG at a Compression Ratio (CR) of 11:1 and engine speed of 1500 rpm from no-load to full load engine operation. Using suitable throttling devices, a 130 bar supply gas cylinder pressure was conditioned along with other devices to operate engine at Naturally Aspirated (NA) mode. The engine was operated close to stoichiometry condition. The engine supported a peak load of 85 % amounting to a torque of 11.89 N-m and brake power of 1.86 kW against a 2.2 kW gasoline mode. A power loss of 15 % was observed and it was attributed to 25 % lower mixture heating value and 13.33 % lower product to reactant conversion ratio of PG. Overall engine operation was found to be satisfactory. This paper also addresses the need for customizing PG-air mixer and zero pressure regulator.

The aim of the article is to analyze the command of a rehabilitation equipment. The presented rehabilitation equipment allows lower limb joints movements, in order to recover their functionality. The rehabilitation movements are known as continuous passive motion, term used in kinetotherapy.The command used is composed by of a pneumatic muscle supplied with air from a pressure proportional regulator and controlled by a reference module. The reference module, by means of rotary potentiometers, can generate up to six different values of ​​reference voltage which are transmitted as signals to the proportional controller. If no appeal to any of these benchmarks, the transmitted signal to the pressure regulator is a voltage that can be modified by an external potentiometer. The results of experiments shows that proportional pressure regulator allows easy modification of the pressure slope, with better results on rehabilitation movements.

In the view of the traditional purely mechanical regulator’s disadvantage, this paper proposed a new type intelligent gas pressure regulator. Its advantage is the ability to achieve accurate output pressure, remote control and centralized management. It can resist the disturbance of inlet pressure and flow rate changes. In this paper, we introduce the regulator’s structure, working principle, mathematics model and simulation model. According to the simulation result, it can basically meet the working demand.

A vortex tube offers an alternative cooling with advantages of simplicity and compact. Using a natural refrigerant, a vortex tube enclosure cooling is environmentally benign. In this paper, the performance of a vortex tube enclosure cooling, VTEC, is investigated experimentally. The VTEC system comprises of the vortex tube cooling, an enclosure with a volume space of 0.045 m3, an air compressor, a compressed air storage tank and a compressed air line. The VTEC system is tested for its efficiency and cooling potential in the laboratory. An operating condition is controlled by a pressure regulator for an inlet air pressure of 3 bars, for energy saving, and a cold flow rate is adjusted by a needle valve near the hot exit of a vortex tube for the cold fraction between 0 and 1. Accordingly, the analysis of experimental data shows the maximum isentropic efficiency of the vortex tube enclosure cooling is 0.37 at the cold mass fraction of 0.45. Air temperature in the enclosure is about 13°C in average.

A simulation based on simulink was set up to investigate the performance of marine refrigeration system. For the simulator focused on the operation and management, so the steady state simulation algorithm is to be used to build simulator of the whole system, it gives consideration to both efficiency and precision of simulation calculation, real-time of operation and management is increased. Compressor thermal model is simple, most of that use steady-state model with no iterative computation. Due to the need of teaching and simulation operation, we use lumped parameter method and partition method to establish mathematical model of Condenser, evaporator, expansion valve, evaporator pressure regulator, cold storage and other parts. True-time operation and the appraisal function has developed. The simulation result accorded well with the experiment result. This model precision is high and timely. It was acceptable used in the ships refrigeration system's operation.

Hydraulic modulator regulates the pressure of four wheels independently to realize the Anti-lock Braking System (ABS) and the Electronic Stability Control (ESC) function. The pressure regulator, also called hydraulic control unit, works by controlling several valves to realize the on-off operation of the liquid paths. This paper focuses on working mechanism and hydraulic response characteristics of inlet valve of hydraulic control unit through simulation analysis.

The static-state error is existed in the pressure valve, coupled with the characteristics of high vaporization pressure, low viscosity, and small compressibility, so that the fluid dynamics and friction force of hydraulic pressure valve are increased. The pressure valve will easily come up with produce cavitation erosion and wire drawing. Those appearances would seriously affect the performance of the pressure valve and its life cycle. A new type of static water pressure reducing valve is designed in this paper. It has a special structure which can complete the internal dynamic pressure feedback of the valve. The static mathematical model of value is established. And the static characteristic is analysed by using MATLAB simulation, which provides the static pressure characteristic curve, static pressure flow curve. It comes up with a result that this valve has good static pressure, and high precision pressure regulator.

The high parameter pressure reducing valve (PRV) is a key device for regulating gas pressure in industrial processes. For the large flow and the instability of the high pressure and high temperature steam, the noise of the working PRV is large and also its energy consumption. A numerical analysis of the flow field and acoustic field of the inner high parameter PRV was conducted, the main cause of the aerodynamic noise was analyzed. Basing on the RNG k-ε Model and the Broadband Noise Source Model, the flow and acoustic power are calculated. Comparing the distribution of acoustic power level with the distribution of the velocity and turbulent intensity, it is shown that the main reasons for noise in the PRV are forming and shedding alternately vortexes and shock waves of jet flow.

KM6 space simulator built in 1990s is currently the largest thermal vacuum test facility for spaceships and satellites in China. In order to meet new requirements of ground test for outer-cabin space walk of astronauts under China Manned Space Project II, a hatch-door system with ten rectangular doors in auxiliary horizontal chamber of KM6 space simulator has been updated since 2006. For the sake of pressure balance, every hatch-door is upgraded with a pressure regulator, which enables easy close and open of every hatch-door under no pressure difference. To improve vacuum compatibility of rotating hatch-doors, single axis hinge mechanism is renewed as biaxial hinge mechanism with more degrees of freedom for door spindle, which is combined with coordinated lock mechanism and O-ring sealing structure to realize the self-alignment sealing of hatch-door flange structure. Up until now, three manned spaceships of SZ-5, SZ-6 and SZ-7 have successfully finish thermal vacuum tests in auxiliary horizontal chamber with high performance of the updated hatch-door system as results.

In order to promote the technical progress of pressure reducing valve in nature gas transport system, a high pressure pilot operated axial-flow pressure reducing valve was designed and developed. The three-dimensional modeling of the natural gas pressure reducing valve internal flow passage was found by using Solidworks software. Import the flow channel model into meshing in CFD software based on the internal flow channel geometry and flow characteristics. The ideal gas compressible fluid model of natural gas and improved RNG k-Epsilon model were used to solve the pressure and velocity distribution as well as other flow related parameters of the natural gas pilot operated pressure reducing valve. The flow fields of the pressure reducing valve with different valve plug shape were analyzed. Changes of valve plug shape were made to improve the performance of the valve.

Reaction control subsystem (RCS) is an onboard satellite propulsion system used to provide required thrusting for orbit raising, orbit maintenance, and attitude control etc.. High pressure flow with high temperature could be generated in a chamber by chemical reactions or other power resources then expelled through a convergent-divergent nozzle to obtain thrust. In order to optimize the thrusting performance, numerical simulation is an efficient method to study the physics and parameters in design phase. In the current study, a hybrid method coupled continuum and particle methods is proposed to simulate flows involving continuum and rarefied regions. The Navier-Stokes (NS) solver named UNIC is developed by Chen and his coworkers. It employs the cell-centered finite-volume method with a hybrid 2D/3D unstructured-grid topology. The proposed particle code named Parallel DSMC Code (PDSC) is a parallelized solver based on the well-known Direct Simulation of Monte Carlo (DSMC) method, which was proposed by Bird in 1976. The physical domain is decomposed into several regimes and each sub-domain executes the serial DSMC code at different processor for speeding up the computing. A practical cold gas thruster with different chamber pressures is simulated by using this hybrid code to study the potential malfunction of the pressure regulator. Then the curve-fitting thrusting equation can be referred to satellite control operations.

The stable output-pressure of a gas regulator has important significance to the operational safety. This new intelligent gas regulator’s key problem is that the output-pressure is difficult to be stable with the single PID control parameters as the initial parameters. For this reason, a Dual-Mode Self-Tuning PID controller is designed, the controller can adjust the Kp, Ki, Kd with different initial value at the different workplace. After simulating with the MATLAB and AMESIM .We find it improves the dynamic property and stable-state property in the natural gas output system effectively. There are practical significance and theoretical reference for the improvement of non-linear industrial control system dynamic behavior.