waterwheels are the oldest types of hydraulic machines. these turbines are of relatively simple design, large diameter, low rotational speed and high torques. but applying them as micro hydros of high speed and small diameter is yet to be explored. a micro hydro waterwheel of one meter diameter was designed and manufactured at the iranian  esearc†h organization for science and technology (irost...

the objective of this research is geometrical optimization of half toroidal continuously variable transmission (cvt) in order to achieve high power transmission efficiency and low weight. after dynamic analysis of the system, the contact between the disk and the roller is modeled according to elasto-hydrodynamic lubrication principles. accordingly, a computer model is created with geometric, th...

Most of the domestic designed hydraulic excavators adopt the constant power design method and set 85%~90% of engine power as the hydraulic system adoption power, it causes high energy loss due to mismatching of power between the engine and the pump. While the variation of the rotational speed of engine could sense the power shift of the load, it provides a new method to adjust the power matchin...

To obtain a good tracking performance in an optical disk drive servo system, it is essential to attenuate periodic disturbances caused by eccentric rotation of the disk. As an effective control scheme for enhancing disturbance attenuation performance, disturbance observers (DOBs) have been successfully applied to the track-following servo system of optical disk drives. In disk drive systems, th...

The optimization of guide vane closing schemes (OGVCS) of pumped storage hydro units (PSHUs) is a cooperative control and optimal operation research field in renewable energy power generation technology. This paper presents an OGVCS model of PSHUs considering the rise rate of the unit rotational speed, the specific node pressure of each hydraulic unit, as well as various complicated hydraulic a...

Centrifugal pumps are an integral part of plants used in process industries. The flow structure within a centrifugal pump is very complex due to the interaction between the rotating impeller and the geometric features around it. In the present study, numerical investigations on a centrifugal pump have been carried out using a Computational Fluid Dynamics (CFD) based solver. This study employs f...