Regions of positive slope in the pressure-discharge characteristics can result in a reduction or even lack of damping of system instabilities. They are therefore one of the major concerns in design and operation of centrifugal pumps as they are limiting the admissible operating range. The considered preliminary hydraulic design of an industrial double suction pump of medium specific speed ν = 0...

The vibration of centrifugal pumps, running at both best efficiency point (BEP) and at low flow, is of interest to both pump designers and users. This vibration is responsible for the poor seal and bearing life and reduced mean time between failure (MTBF). The cause of vane pass vibration and multiples of this are explained in this paper. The causes of low flow vibrations are also explored. The...

Abstract It is of great practical value to complete the low-pressure casting aluminum alloy impeller in current development process. In research, it necessary focus on factory realization and use produce impellers, so that castings with compact structure meeting performance requirements can be obtained. Compared other methods, itself, as a precision method, cast metal solution lower pressure ap...

A standardized and cost-effective risk assessment toolkit is described in this paper to comprehensively analyze centrifugal compressor impellers under steady and dynamic loads. The first step in this process occurs in the proposal stage where the gas loading levels are appraised using a preliminary screening computer program. The application engineers execute the product configuration program f...

In tidal two-way contra-rotating units, significant differences in performance often occur when arranging the front and rear impellers, which requires an optimized design of impellers. To solve this problem, by reducing blade inlet outlet angles, impact different angles on pump–turbines internal flow was explored, effects angle impellers counter-rotating pump were obtained. Afterward, streamlin...

the multiple reference frames (mrf) method is the most suitable method tosimulate impeller rotation in mixing systems. precise determination of stationaryand moving zones in mrf method leads to accurate results in mixing performance.in this research, the entire volume of mixing system was divided into two zones.the kinetic energy values were used to distinguish the zones with differentvelocitie...

Multiphase impeller stirred tank reactors enhance mixing of reacting species used in a variety of chemical industries. These reactors have been studied based on Computational Fluid Dynamics (CFD) that can be used in the analysis, design and scale up of these reactors. Most of the researches done in this area are limited to single phase reactors, and a few remaining two phase flow investigat...

In order to solve the problems of lack of heart donors for transplant, implantable ventricular assist systems (VAS) have been developed to assist the failing heart ventricle. One of the components of a VAS is a blood pump that connects the left ventricle to the aorta. Therefore, the pump flow rate is influenced by the cardio-vascular system. To control the flow rate through the blood pump, real...

Along with the developments of high-speed and highperformance turbomachines, there has been increasing occurrence of rotational speeds higher than the first critical speed. Under these circumstances, turbomachines may suffer from severe vibration and rotor whirl caused by fluid-dynamic forces. As possible causes of whirling instabilities, fluid forces on journal bearings and seals are well know...

Abstract To design a green energy-saving heating pipe, this paper studied the structural transformation of pipe and carried out effect simulation analysis. The key is to add an impeller device inside ordinary convert part kinetic energy fluid in into mechanical impeller. generated by rotation can be transferred through gears, connecting rods, other components converted heat for recovery boiler ...