scholarly journals The Influence of Concentration on The Suction Performance of Dredging Pumps.(Dept.M)

2021 ◽  
Vol 6 (1) ◽  
pp. 112-120
Author(s):  
Magdy Mohamed Abou Rayan ◽  
N. Gadelhak
Keyword(s):  
Suction Performance

scholarly journals On the Improvement in the Suction Performance of High-Head Axial-Flow Pumps

1968 ◽  
Vol 11 (48) ◽  
pp. 1056-1067
Author(s):  
Taijiro KASAI ◽  
Sigenori MATSUNAGA ◽  
Yukio KUNIKIYO ◽  
Haruo ISIBASI
Keyword(s):  
Axial Flow ◽  
High Head ◽  
Suction Performance

Effect of Tip Clearance on Suction Performance at Different Flow Rates in a Mixed Flow Pump

2014 ◽  
Author(s):  
Yo Han Jung ◽  
Young Uk Min ◽  
Jin Young Kim
Keyword(s):  
Performance Test ◽  
Stokes Equations ◽  
Flow Characteristics ◽  
Tip Clearance ◽  
Low Flow ◽  
Tip Leakage Flow ◽  
Mixed Flow ◽  
Flow Rates ◽  
Suction Performance ◽  
Flow Pump

This paper presents a numerical investigation of the effect of tip clearance on the suction performance and flow characteristics at different flow rates in a vertical mixed-flow pump. Numerical analyses were carried out by solving three-dimensional Reynolds-averaged Navier-Stokes equations. Steady computations were performed for three different tip clearances under noncavitating and cavitating conditions at design and off-design conditions. The pump performance test was performed for the mixed-flow pump and numerical results were validated by comparing the experimental data for a system characterized by the original tip clearance. It was shown that for large tip clearance, the head breakdown occurred earlier at the design and high flow rates. However, the head breakdown was quite delayed at low flow rate. This resulted from the cavitation structure caused by the tip leakage flow at different flow rates.

Design Optimization of Cryogenic Pump Inducer Considering Suction Performance and Cavitation Instability

2011 ◽  
Author(s):  
Hiroyoshi Watanabe ◽  
Hiroshi Tsukamoto
Keyword(s):  
Pressure Distribution ◽  
Design Optimization ◽  
Surface Pressure ◽  
Design Approach ◽  
Inverse Design ◽  
Blade Surface ◽  
Free Vortex ◽  
Surface Pressure Distribution ◽  
Cavitation Instability ◽  
Suction Performance

This paper presents the result of design optimization for three-bladed pump inducer using a three-dimensional (3-D) inverse design approach, Computational Fluid Dynamics (CFD) and DoE (Design of Experiments) taking suction performance and cavitation instability into consideration. The parameters to control streamwise blade loading distribution and spanwise work (free vortex or non-free vortex) for inducer were chosen as design optimization variables for the inverse design approach. Cavitating and non-cavitating performances for inducers designed using the design variables arranged in the DoE table were analyzed by steady CFD. Objective functions for non-cavitating operating conditions were the head and efficiency of inducers at a design flow (Qd), 80% Qd and 120% Qd. The volume of the inducer cavity region with a void ratio above 50% was selected as the objective function for inducer suction performance. In order to evaluate cavitation instability by steady CFD, the dispersion of the blade surface pressure distribution on each blade was selected as the evaluation parameter. This dispersion of the blade surface pressure distribution was caused by non-uniformity in the cavitation length that was developed on each inducer blade and increased when the cavitation number was reduced. The effective design parameters on suction performance and cavitation instability were confirmed by sensitivity analysis during the design optimization process. Inducers with specific characteristics (stable, unstable) designed using the effective parameters were evaluated through experiments.

Critical Suction Peformance Test of Turbopump Assembly for a Liquid-Propellant Rocket Engine

2018 ◽  
Author(s):  
Hang Gi Lee ◽  
Ju Hyun Shin ◽  
Suk Hwan Yoon ◽  
Dae Jin Kim ◽  
Jun Hwan Bae ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Performance Test ◽  
Rocket Engine ◽  
Lightweight Design ◽  
Cavitation Number ◽  
Inlet Pressure ◽  
Liquid Oxygen ◽  
Pump Failure ◽  
Critical Cavitation ◽  
Suction Performance

This study investigates the behavior of a turbopump assembly during critical cavitation of the propellant pumps in the upper rocket engine of the Korea Space Launch Vehicle-II. Turbopumps operate under conditions involving low pressure at the pump inlet and high rotational speeds to allow for a lightweight design. This severe environment can easily cause cavitation to occur in the pump. This cavitation can then cause the pump operation to fail. As the cavitation number in the pump decreases below the critical point, the pump fails to operate. There is concern regarding the behavior of the turbopump assembly arising from pump failure due to cavitation. It is necessary to verify the problems that may occur if the turbopump assembly operates under extreme conditions, such like the critical cavitation. This study performed tests to investigate the breakdown of pumps in the turbopump assembly. Tests were conducted with liquid nitrogen, water, and high-pressure air instead of the mediums used during actual operation of liquid oxygen, kerosene, and hot gas. The turbopump was tested at the design point of 27,000 rpm, while the inlet pressure of each pump was controlled to approach the critical cavitation number. The turbine power output was maintained during the tests. The results show that the breakdown point of the oxidizer pump using liquid nitrogen, which is a cryogenic medium, occurred at a lower cavitation number than during an individual component suction performance test using water. The fuel pump using water, meanwhile, experiences breakdown at similar cavitation numbers in both tests. As the breakdown of the pump occurs, the power required by that pump decreases, and the rotational speed of the turbopump increases. Compared with individual pump suction performance tests, this breakdown test can be used to determine the limit of the propellant inlet pressure of the turbopump and to characterize the behavior of the turbopump assembly when a breakdown occurs. Vibrations were also analyzed for tests at a high cavitation number and at the critical cavitation number. The vibration increased with breakdown and notable frequencies were analyzed.

scholarly journals Investigations of Inducers Operating With High Rotational Speed

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Björn Gwiasda ◽  
Matthias Mohr ◽  
Martin Böhle
Keyword(s):  
Rotational Speed ◽  
Test Bench ◽  
Pressure Rise ◽  
Working Fluid ◽  
Cfd Simulations ◽  
High Rotational Speed ◽  
Rotating Speed ◽  
Performance Pressure ◽  
Computational Fluid Dynamics Cfd ◽  
Suction Performance

Suction performance, pressure rise, and efficiency for four different inducers are examined with computational fluid dynamics (CFD) simulations and experiments performed with 18,000 rpm and 24,000 rpm. The studies originate from a research project that includes the construction of a new test bench in order to judge the design of the different inducers. This test bench allows to conduct experiments with a rotational speed of up to 40,000 rpm and high pressure ranges from 0.1 bar to 40 bar with water as working fluid. Experimental results are used to evaluate the accuracy of the simulations and to gain a better understanding of the design parameter. The influence of increasing the rotating speed from 18,000 rpm to 24,000 rpm on the performance is also shown.

scholarly journals Hydrodynamic modelling of aquatic suction performance and intra-oral pressures: limitations for comparative studies

2006 ◽  
Vol 3 (9) ◽  
pp. 507-514 ◽  
Author(s):  
Sam Van Wassenbergh ◽  
Peter Aerts ◽  
Anthony Herrel
Keyword(s):  
Hydrodynamic Force ◽  
Ambient Pressure ◽  
Simple Relationship ◽  
Suction Feeding ◽  
Aquatic Animals ◽  
Future Studies ◽  
Pharyngeal Cavity ◽  
Oral Pressure ◽  
Direct Indication ◽  
Suction Performance

The magnitude of sub-ambient pressure inside the bucco-pharyngeal cavity of aquatic animals is generally considered a valuable metric of suction feeding performance. However, these pressures do not provide a direct indication of the effect of the suction act on the movement of the prey item. Especially when comparing suction performance of animals with differences in the shape of the expanding bucco-pharyngeal cavity, the link between speed of expansion, water velocity, force exerted on the prey and intra-oral pressure remains obscure. By using mathematical models of the heads of catfishes, a morphologically diverse group of aquatic suction feeders, these relationships were tested. The kinematics of these models were fine-tuned to transport a given prey towards the mouth in the same way. Next, the calculated pressures inside these models were compared. The results show that no simple relationship exists between the amount of generated sub-ambient pressure and the force exerted on the prey during suction feeding, unless animals of the same species are compared. Therefore, for evaluating suction performance in aquatic animals in future studies, the focus should be on the flow velocities in front of the mouth, for which a direct relationship exists with the hydrodynamic force exerted on prey.

Increasing Inducer Stability and Suction Performance With a Stability Control Device

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
R. Lundgreen ◽  
D. Maynes ◽  
S. Gorrell ◽  
K. Oliphant
Keyword(s):  
Fluid Dynamic ◽  
Leading Edge ◽  
High Energy ◽  
Stability Control ◽  
Control Device ◽  
Design Flow ◽  
Flow Coefficient ◽  
Blade Tip ◽  
Rotordynamic Forces ◽  
Suction Performance

An inducer is used as the first stage of high suction performance pump. It pressurizes the fluid to delay the onset of cavitation, which can adversely affect performance in a centrifugal pump. In this paper, the performance of a water pump inducer has been explored with and without the implementation of a stability control device (SCD). This device is an inlet cover bleed system that removes high-energy fluid near the blade leading edge and reinjects it back upstream. The research was conducted by running multiphase, time-accurate computational fluid dynamic (CFD) simulations at the design flow coefficient and at low, off-design flow coefficients. The suction performance and stability for the same inducer with and without the implementation of the SCD has been explored. An improvement in stability and suction performance was observed when the SCD was implemented. Without the SCD, the inducer developed backflow at the blade tip, which led to rotating cavitation and larger rotordynamic forces. With the SCD, no significant cavitation instabilities developed, and the rotordynamic forces remained small. The lack of cavitation instabilities also allowed the inducer to operate at lower inlet pressures, increasing the suction performance of the inducer.

Parametric Design of a Waterjet Pump by Means of Inverse Design, CFD Calculations and Experimental Analyses

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Duccio Bonaiuti ◽  
Mehrdad Zangeneh ◽  
Reima Aartojarvi ◽  
Jonas Eriksson
Keyword(s):  
Flow Field ◽  
Parametric Study ◽  
Parametric Design ◽  
Inverse Design ◽  
Design Parameters ◽  
Pump Design ◽  
Hydrodynamic Efficiency ◽  
Numerical Predictions ◽  
High Level ◽  
Suction Performance

The present paper describes the parametric design of a mixed-flow water-jet pump. The pump impeller and diffuser geometries were parameterized by means of an inverse design method, while CFD analyses were performed to assess the hydrodynamic and suction performance of the different design configurations that were investigated. An initial pump design was first generated and used as baseline for the parametric study. The effect of several design parameters was then analyzed in order to determine their effect on the pump performance. The use of a blade parameterization, based on inverse design, led to a major advantage in this study, because the three-dimensional blade shape is described by means of hydrodynamic parameters, such as blade loading, which has a direct impact on the hydrodynamic flow field. On the basis of this study, an optimal configuration was designed with the aim of maximizing the pump suction performance, while at the same time, guaranteeing a high level of hydrodynamic efficiency, together with the required mechanical and vibrational constraints. The final design was experimentally tested, and the good agreement between numerical predictions and experimental results validated the design process. This paper highlights the contrasting requirements in the pump design in order to achieve high hydrodynamic efficiency or good cavitation performance. The parametric study allowed us to determine design guidelines in order to find the optimal compromise in the pump design, in cases where both a high level of efficiency and suction performance must simultaneously be achieved. The design know-how developed in this study is based on flow field analyses and on hydrodynamic design parameters. It has therefore a general validity and can be used for similar design applications.

Diagonal Flow Pump Impeller With NACA65 Series Blade (Correction of Blade Geometry)

2011 ◽  
Author(s):  
Yoichi Kinoue ◽  
Norimasa Shiomi ◽  
Toshiaki Setoguchi ◽  
Kazuhiro Sawamura ◽  
Hideaki Maeda
Keyword(s):  
Rotor Blade ◽  
Design Flow ◽  
Numerical Calculations ◽  
Navier Stokes ◽  
Minimum Pressure ◽  
The One ◽  
Suction Performance ◽  
Flow Pump ◽  
Better Than ◽  
Blade Geometry

Using the design method based on the design for axial-flow type turbomachine, the diagonal flow pump impellers were designed for two cases of the centrifugal effect parameter a. In addition, three-dimensional Navier-Stokes numerical calculations for single-phase were conducted in order to examine the tendency of the suction performance as well as the head performance. The head increases from the NS calculation of the impeller are the same between for a = 0.4 and for a = 1.0 because major specification are the same between for a = 0.4 and for a = 1.0. For the minimum pressure on the rotor blade, however, there is a difference between for a = 0.4 and for a = 1.0. The value of minimum pressure for a = 0.4 is −324 kPa, whereas the value for a = 1.0 is −294 kPa. The blade geometry for a = 1.0 is better than the one for a = 0.4 in terms of the suction performance because the trough of the minimum pressure is shallower for a = 1.0 than a = 0.4. Furthermore, Navier-Stokes numerical calculations were also conducted for off-design flow rate. For all cases in this paper, the minimum pressure on the rotor blade occurred at both near the leading edge and near the tip on the suction side of the blade. In addition, for all cases in this paper, the blade geometry for a = 1.0 is better than the one for a = 0.4 in terms of the suction performance.

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