The aortic valve operates in a complex haemodynamic environment, opening and closing over 100,000 times a day. When complications arise, such as aortic stenosis, prognosis can be very poor, leading to death within the first few years. Surgical valve replacement is currently the standard treatment for aortic stenosis. A thorough understanding of the anatomy and function of the native valve is im...

Variable valve timing allows improvements of internal combustion engines and can be achieved by camless actuation technology. In this paper we consider an electromechanical valve (EMV) actuator. One of the main problems in the EMV actuator is the noise and wear associated with high contact velocities during the closing and opening of the valve. The contact velocity of the actuator parts can be ...

Due to the stringent legislation for emission of diesel engines and also increasing demand on fuel consumption, the importance of detailed 3D simulation of fuel injection, mixing and combustion have been increased in the recent years. In the present work, FIRE code has been used to study the detailed modeling of spray and mixture formation in a Caterpillar heavy-duty diesel engine. The paper pr...

Water-hammer is a transient condition which may occur in a network as a result of rapid or slow valve closures, pump failures, changes in turbine loading, etc. It creates high and low pressure waves which travel along the system and decay as a result of wall shear stress. Comparison o experimental and theoretical results revealed the failure of steady or quasi-steady models in correctly predict...

This paper investigates multiple-valve closures in a simple reservoir-valve-pipeline-valve system. Multiple closing (or opening) of valves may induce large positive or low negative pressure waves due to wave interference (superposition the waves). The effect closure can be either beneficial detrimental, with outcome being entirely dependent on position and sequence delay closures. Valves are in...

Recently, there have been more reports of cardiac valve infections due to the increasing number of intravenous (IV) drug abusers and chronic renal failure patients. Among cardiac valves, tricuspid valve is most commonly affected in the course of endocarditis. Appropriate management of these patients is a challenging and controversial issue in the field of cardiac surgery. Treatment options in s...

In order to improve the reliability of tripping solenoid valve and switching steam turbine in nuclear power plant reduce abnormal closing. According working principle valves plant, this paper designs a kind electromagnetic sealing test system, including base, measurement control system hydraulic system. The detection is an offline By simulating real load condition tightness tested valve. actual...

The purpose of a prosthetic cardiac valve is to restore the function of a diseased aortic or mitral valve, and its role in haemodynamics is a passive one: the opening and closing of such a valve is strictly regulated by the pressure differences in the cardiac chambers which communicate through this valve. Therefore we consider that a prosthetic valve should be tested under conditions simulating...