A Study on Back Flow Structure in a 2-Bladed Helical Inducer at a Partial Flow Rate

2009 ◽  
Author(s):  
Satoshi Watanabe ◽  
Naoki Inoue ◽  
Koichi Ishizaka ◽  
Akinori Furukawa ◽  
Jun-Ho Kim
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Flow Simulation ◽  
Internal Flow ◽  
Back Flow ◽  
Rate Region ◽  
Numerical Studies ◽  
The Difference ◽  
Throat Section ◽  
Suction Performance

The attachment of inducer upstream of main impeller is an effective method to improve the suction performance of turbopump. However, various types of cavitation instabilities are known to occur even at the designed flow rate as well as in the partial flow rate region. The cavitation surge occurring at partial flow rates is known to be strongly associated with the inlet back flow. In the present study, in order to understand the detailed structure of internal flow of inducer, we firstly carried out the experimental and numerical studies of non-cavitating flow, focusing on the flow field near the inlet throat section and inside the blade passage of a two bladed inducer at a partial flow rate. The steady flow simulation with cavitation model was also made to investigate the difference of the flow field between in the cavitating and non-cavitating conditions.

Effect of Leading Edge Sweep on Cavitation Performance of Two-Bladed Flat Plate Inducer

2011 ◽  
Author(s):  
Takaki Igoshi ◽  
Yuki Uchinono ◽  
Emosi Koroitamana ◽  
Koichi Ishizaka ◽  
Satoshi Watanabe ◽  
...  
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Internal Flow ◽  
Leading Edge ◽  
Pressure Measurements ◽  
Flow Measurements ◽  
Cavitation Performance ◽  
Video Observations ◽  
Flow Rate Range ◽  
Suction Performance

The installation of inducer upstream of main impeller is an effective method to improve the suction performance of turbopump. However, various types of cavitation instabilities are known to occur even at the designed flow rate as well as in the partial flow rate range. In the present study, we focus on the leading edge sweep of inducer and investigate its effect on the suction performance as well as on the onset of cavitation surge phenomenon. Flow measurements including casing wall pressure measurements, high-speed video observations, and limiting streamline observations are carried out, and discussions will be made based on those results about the influence of backward leading edge sweep on the internal flow of the inducer as well as its relation to the cavitation performance.

scholarly journals Inverse Design of Centrifugal Compressor Vaned Diffusers in Inlet Shear Flows

1994 ◽  
Author(s):  
M. Zangeneh
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Design Method ◽  
Internal Flow ◽  
Inviscid Flow ◽  
Inverse Design ◽  
Navier Stokes ◽  
Inlet Flow ◽  
Blade Thickness ◽  
The Difference

A 3D inverse design method in which the blade (or vane) geometry is designed for specified distributions of circulation and blade thickness is applied to the design of centrifugal compressor vaned diffusers. Two generic diffusers are designed, one with uniform inlet flow (equivalent to a conventional design) and the other with a sheared inlet flow. The inlet shear flow effects are modelled in the design method by using the so-called “Secondary Flow Approximation” in which the Bernoulli surfaces are convected by the tangentially mean inviscid flow field. The difference between the vane geometry of the uniform inlet flow and non-uniform inlet flow diffusers is found to be most significant from 50% chord to the trailing edge region. The flow through both diffusers are computed by using Denton’s 3D inviscid Euler solver and Dawes’ 3D Navier-Stokes solver under sheared inflow conditions. The predictions indicate improved pressure recovery and internal flow field for the diffuser designed for shear inlet flow conditions.

scholarly journals Air Flow Simulation and Optimization for Negative Pressure Safflower Harvesting Device

2015 ◽  
Vol 9 (1) ◽  
pp. 773-779 ◽  
Author(s):  
Ge Yun ◽  
Zhang Lixin ◽  
Han Dandan ◽  
Zeng Haifeng ◽  
Zhang Xiang
Keyword(s):  
Flow Field ◽  
Air Flow ◽  
Flow Simulation ◽  
Internal Flow ◽  
Parabolic Type ◽  
Flow Speed ◽  
Low Velocity ◽  
Simulation And Optimization ◽  
Airflow Distribution ◽  
Cone Type

The safflower collection device is an important service part of safflower harvesting device, the number of the air outlets and external structure of air collecting hood are the main factors influencing the effect of the flower’s petals harvesting and collection. However, the design of pneumatic safflower harvest device is based on experience, resulting in long the design cycle, thus increasing the cost of design. Combined with the advantages of computational fluid dynamics software FLUENT, and the internal flow field of safflower closed style cover flowers as the research object, this paper designed gas collecting hood structures with different number of outlets through the analysis of the airflow distribution and motion law. The result of numerical simulation of gas-collecting hood with trapezoidal cone shows higher air flow speed with no low velocity zone, and the distribution of flow field of safflower collected cover with trapezoid cone type is better than that of parabolic type structure. Based on result of simulation, improved the design of the external shape of flowers cover and designed trapezoid cone type to improve the internal airflow state, thus could achieve the goal of improving efficiency of picking and collecting and reduce energy consumption.

scholarly journals Experimental study on fiber suspensions in a curved expansion duct with particle image velocimetry

2012 ◽  
Vol 16 (5) ◽  
pp. 1414-1418 ◽  
Author(s):  
Xiao-Yu Liang ◽  
Huan-Huan Wu ◽  
Cheng-Xu Tu ◽  
Kai Zhang
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Flow Rate ◽  
Particle Image ◽  
Flow Direction ◽  
Internal Flow ◽  
Concave Wall ◽  
Image Velocimetry ◽  
Inlet Flow Rate ◽  
Convex Wall

The visualization measurement of internal flow field in a curved expansion duct is experimentally studied using particle image velocimetry technology and the influence of flow rate on flow field is analyzed. The streamline distribution and related performance curve in the internal flow field can be figured out through further analysis of experiment data. The results show that fiber orientation is mainly affected by velocity gradient, the fibers near the wall are aligned with the flow direction more quickly than the fibers in intermediate region, and the fibers near the concave wall are more quickly aligned with the flow direction than the convex wall. The larger inlet flow rate which will accordingly lead to increase inlet velocity enables the more quick adaptation and steady of fibers in flow direction.

Experimental and Numerical Studies of the Velocity Field of a Triple Annular Swirler

2002 ◽  
Author(s):  
Guoqiang Li ◽  
Ephraim J. Gutmark
Keyword(s):  
Flow Field ◽  
Fuel Injection ◽  
Internal Flow ◽  
Atmospheric Conditions ◽  
Cold Flow ◽  
Numerical Studies ◽  
Annular Jet ◽  
Velocity Flow ◽  
Industrial Gas Turbine ◽  
Rotational Direction

Modern industrial gas-turbine spray combustors feature multiple swirlers and distributed fuel injection for rapid mixing and stabilization. The present paper is the first of a sequence of papers that aim to study the flow field of such combustors, the related combustion characteristics and their control. The present paper focuses on an experimental investigation of the velocity flow field downstream of a Triple Annular Swirler (TAS) and CFD description of the flow field inside the TAS. Multiple combinations of swirlers of various swirl level and rotational direction were tested in cold flow under atmospheric conditions without a confining combustion chamber. The experiments showed that a Central Toroidal Recirculation Zone (CTRZ) and an annular jet with internal and external shear layers characterize the flow field downstream of TAS. The CTRZ is axisymmetric but the jet contains imprints of the internal flow and has some nonaxisymmetric features. Numerical RANS results confirmed these observations and showed that the asymmetry relates to the effect of the internal swirling vanes on the jet flow.

scholarly journals Computational Fluid Dynamic Analysis of Flow Rate Performance of a Small Piezoelectric-Hydraulic Pump

2021 ◽  
Vol 11 (11) ◽  
pp. 4888
Author(s):  
Phuc Nguyen Anh ◽  
Jae-Sung Bae ◽  
Jai-Hyuk Hwang
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Transient Flow ◽  
Fluid Dynamic ◽  
Check Valve ◽  
Internal Flow ◽  
Pump Efficiency ◽  
Rate Performance ◽  
Hydraulic Pump ◽  
Computational Fluid Dynamic Analysis

This paper investigates the transient flow rate performance of small piezoelectric-hydraulic pumps. In a previous study, a small piezoelectric hydraulic pump was designed and developed to be applicable to the braking systems of small- and medium-sized UAVs (unmanned aerial vehicles). To this end, a thin plate spring check valve was designed in order to effectively discharge the flow in a single direction. The flow rate of the piezoelectric-hydraulic pump is an important criterion for evaluating pump efficiency. Therefore, a study on the parameters affecting such a flow rate is necessary to enhance the efficiency of piezoelectric hydraulic pumps used in brake systems. This study on small piezoelectric-hydraulic pumps is performed to accurately predict the flow rate using a CFD (Computational Fluid Dynamics) tool. In other words, an unsteady CFD method is applied to model the transient flow rate characteristics and the internal flow field of the fluid. The visualization of the internal flow field is evaluated for a better understanding of the flow fields inside the pump. Moreover, this work also illustrates the detailed motion of both the inlet and outlet check valves during the pump operation that fully reflects the phase shift between the check valves and the piston motion, all of which affect the flow rate performance of the pump. An experiment of flow rate characteristics was conducted on a designed piezoelectric-hydraulic pump, which verifies the validity of the CFD results.

Experiment and Optimization of Settling Effect of Drip Streaming Filter

2014 ◽  
Vol 620 ◽  
pp. 246-253
Author(s):  
Su Zhen Wu ◽  
Han Song Yang
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Simulation Analysis ◽  
Structural Parameters ◽  
Internal Flow ◽  
Tube Insertion ◽  
Insertion Depth ◽  
Sediment Production ◽  
Fluent Software ◽  
The Relationship

In this thesis, by changing the filter overflow tube insertion depth of spin streaming filter, combined with the existing drip irrigation equipment change the structure parameters of spin streaming filter. Using Fluent software to choose reasonable turbulence model for numerical simulation analysis, contrastive research on the field test was carried on, reveals the relationship between the internal flow field pressure and the flow rate. The sediment production increased before they are reduced with the increase of the overflow tube insertion depth. It should choose the optimal insertion depth according to the specific use and usage model of hydrocyclone in actually use. The variation trend of internal flow field pressure and the flow rate when selected structural parameters changed are also analyzed. With the increase of insertion depth, the axial velocity and radial velocity of sand and water inside the hydrocyclone shows the tendency of decrease. Furthermore, the field experiment verifies the simulation result, thus proving the feasibility of using Fluent computational fluid dynamics software to simulate the internal flow field of the spin streaming filter. The research results will provide referential basis for the design and application of the drip filter system.

Numerical/Experimental Investigations on Inlet Back Flow in a Helical Inducer in Partial Flow Conditions

2007 ◽  
Author(s):  
Satoshi Watanabe ◽  
Jun-Ho Kim ◽  
Koichi Ishizaka ◽  
Akinori Furukawa
Keyword(s):  
Flow Rate ◽  
Experimental Investigations ◽  
Cavitating Flows ◽  
Flow Conditions ◽  
Detailed Structure ◽  
Flow Rates ◽  
Back Flow ◽  
Effective Suppression ◽  
Basic Characteristics ◽  
Suction Performance

The attachment of inducer upstream of main impeller is an effective method to improve the suction performance of turbopumps. However, the various types of cavitation instabilities are known to occur even at the designed flow rate as well as in the partial flow rate conditions. The cavitation surge is a viciously unstable phenomenon occurring at partial flow rates, in which all blade cavities are periodically and synchronously elongated and shortened, leading the strong vibration in pump systems. Because the cavitation surge is strongly associated with the inlet back flow of inducer, it is desirable to know the detailed structure of back flow for the development of its effective suppression methods/devices. Then, in the present study, we carried out the numerical and experimental investigations of non-cavitating flows in a two bladed helical inducer with/without an inlet ring plate, which has been found to be effective for the suppression of cavitation surge. The basic characteristics of the inlet back flow structure are obtained and discussed in terms of the occurrence/suppression mechanisms of cavitation surge.

Interaction Between Surge Behavior and Internal Flow Field in an Axial-Flow Compressor

2018 ◽  
Author(s):  
Yuu Sakata ◽  
Nobumichi Fujisawa ◽  
Yutaka Ohta
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Pressure Fluctuation ◽  
Rapid Change ◽  
Internal Flow ◽  
Rotating Stall ◽  
Back Pressure ◽  
Rate Of Change ◽  
Operating Point ◽  
Tank Pressure

Interaction between surge behavior and internal flow field under coexisting phenomena of surge and rotating stall was experimentally investigated. In the experiment, the tank pressure of the compressor during surge was measured to detect the effect of the back-pressure fluctuation on the change in the internal flow field. Furthermore, the rotating stall in the compressor was investigated to define the influence of an unsteady internal flow field change on the surge behavior. From the tank pressure measurements, the amplitude of the tank pressure fluctuation was found to vary depending on the cycle. A larger maximal value for the tank pressure fluctuation led to a higher flow rate where the stall inception occurred. This difference in the flow rate indicated that the stall was induced by a severe adverse pressure gradient in the compressor. Then, the absolute rate of change in the flow coefficient was increased by both a large decrease in the compressor back pressure and performance degradation from stalling. In a case where the rate of decline in the flow rate was large, the scale of the stall cell developed up to a deep stall according to the movement of the operating point. Thus, a large trajectory for the surge cycle was selected, where the unsteady operating point went through the deep stall region. This development in the scale of the stall cell suggested to be influenced by the instability of the inner flow field caused by the rapid change in the flow rate.

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