surge is one of the two destructive factors in compressors. surge is the stream instability phenomenon in compressor that imposes severe damages to the compressors. nowadays, suppressingsurge phenomenon is one of the most important issues in oil and gas industries, especially when flow reduction or gas reflux is considered. according to moore-greitzer compressor model, this paper designs an act...

In this study it has been tried, to compare results and convergence rate of sensitivity analysis and conjugate gradient algorithms to reduce fuel consumption and increasing engine performance by optimizing the timing of opening and closing valves in XU7/L3 engine. In this study, considering the strength and accuracy of simulation GT-POWER software in researches on the internal combustion engine...

Abstract Flow resistance characteristic is an important parameter in the design of solenoid valve. It not only affects determination structural parameters valve, but also plays a decisive role selection control method In this paper, flow curve valve obtained based on 3D steady-state CFD simulation.

Electro-hydraulic proportional control valves are widely applied for motion control in the electro-hydraulic fluid power system. Normally, a sliding spool is used in the proportional control valve to control the flow direction and flow rate passing through the valve, as a result, the meterin and meter-out orifices are mechanically connected [1]. The sliding spool makes the system robust and eas...

The control valve operates at high operation frequency (up to 1,000 Hz) in the large pressure differences between the inlet and outlet of the valve. The flow and operation characteristics of a high-speed electromagnetic control valve are investigated using a commercial software, CFD-ACE+. It is found that maximum operation frequency of the control valve depends on the applied electromagnetic fo...

This paper proposes a structure and control approach for the energy saving servo control of a pneumatic servo system. The energy saving approach is enabled by supplementing a standard four-way spool valve controlled pneumatic actuator with an additional two-way valve that enables flow between the cylinder chambers. The “crossflow” valve enables recirculation of pressurized air, and thus enables...

Pneumatic control valves are still the most used in process industries due to their low cost and simplicity. This paper presents a design procedure of a PID controller for a pneumatic control valve. For comparison, P and PI controllers are also utilized for the control valve. The bond graph method is used to model the control valve, in order to compare the response characteristics of the valve....

purpose: to evaluate the effect of early aqueous suppressants initiation on ahmed glaucoma valve success rate. methods: in this randomized clinical trial, a total of 94 eyes of 94 patients with refractory glaucoma were enrolled. the eyes were randomly selected into 2 groups. in group 1 (n=47), patients received early topical combination of timolol-dorzolamide twice daily after ahmed glaucoma va...

in this study it has been tried, to compare results and convergence rate of sensitivity analysis and conjugate gradient algorithms to reduce fuel consumption and increasing engine performance by optimizing the timing of opening and closing valves in xu7/l3 engine. in this study, considering the strength and accuracy of simulation gt-power software in researches on the internal combustion engine...