scholarly journals The Influence of the Blade Outlet Angle on the Flow Field and Pressure Pulsation in a Centrifugal Fan

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1422
Author(s):  
Hongchang Ding ◽  
Tao Chang ◽  
Fanyun Lin
Keyword(s):  
Flow Field ◽  
Pressure Fluctuations ◽  
Great Influence ◽  
Internal Flow ◽  
Turbulent Energy ◽  
Design Flow ◽  
Centrifugal Fan ◽  
Frequency Multiplication ◽  
Outlet Angle ◽  
Blade Frequency

This paper takes centrifugal fan as the research object and establishes five impeller models with different blade outlet angles. By means of computational fluid dynamics (CFD), the external characteristics of the centrifugal fan and the internal characteristics, including the velocity, pressure, and turbulent energy distribution, at the middle span plane of the impeller or fan were obtained and compared. In addition, the pressure fluctuations surrounding the impeller outlet were also analyzed. The results showed that the change of the blade outlet angle of the centrifugal fan had a great influence on the performance; the total pressure and efficiency of the fan were the highest when the outlet angle of the blade was increased to 29.5° under the design flow rate; and the influence of the outlet angle on the fan performance was different in off-design conditions. On the other hand, at different flow rates, the change of the internal flow field with the increase of the outlet angle was different. For the pressure fluctuation of the fan, by increasing the blade outlet angle properly under high flow conditions, the fluctuation amplitude of the fan at the blade frequency and its frequency multiplication could be reduced, which is conducive to decreasing the impeller noise. The research results have good guiding significance regarding the design of the pneumatic performance and noise reduction performance of centrifugal fans.

scholarly journals Analysis of the Influence of Different Bionic Structures on the Noise Reduction Performance of the Centrifugal Pump

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 886
Author(s):  
Cui Dai ◽  
Chao Guo ◽  
Yiping Chen ◽  
Liang Dong ◽  
Houlin Liu
Keyword(s):  
Flow Field ◽  
Noise Reduction ◽  
Centrifugal Pump ◽  
Great Influence ◽  
Frequency Doubling ◽  
Sound Field ◽  
Internal Flow ◽  
Test System ◽  
Centrifugal Pumps ◽  
External Characteristics

The strong noise generated during the operation of the centrifugal pump harms the pump group and people. In order to decrease the noise of the centrifugal pump, a specific speed of 117.3 of the centrifugal pump is chosen as a research object. The bionic modification of centrifugal pump blades is carried out to explore the influence of different bionic structures on the noise reduction performance of centrifugal pumps. The internal flow field and internal sound field of bionic blades are studied by numerical calculation and test methods. The test is carried out on a closed pump test platform which includes external characteristics and a flow noise test system. The effects of two different bionic structures on the external characteristics, acoustic amplitude–frequency characteristics and flow field structure of a centrifugal pump, are analyzed. The results show that the pit structure has little influence on the external characteristic parameters, while the sawtooth structure has a relatively great influence. The noise reduction effect of the pit structure is aimed at the wide-band noise, while the sawtooth structure is aimed at the discrete noise of the blade-passing frequency (BPF) and its frequency doubling. The noise reduction ability of the sawtooth structure is not suitable for high-frequency bands.

Digital Analysis of Hydraulic Cone Valve Turbulence Based on Fluent 3D Solver

2013 ◽  
Vol 385-386 ◽  
pp. 93-96
Author(s):  
Hong Ji ◽  
Wei Guo Zhu ◽  
Song Chen ◽  
Jing Zhao
Keyword(s):  
Flow Field ◽  
Great Influence ◽  
Internal Flow ◽  
Energy Utilization ◽  
Valve Seat ◽  
Taper Angle ◽  
Turbulent Characteristics ◽  
Hydraulic Hammer ◽  
Drive And Control ◽  
And Control

The hydraulic cone valve is an important basic component in Fluid drive and control technology. Characteristic of cone valve inner flow filed influences directly the valves performance. Especially when fluid flow in runner is turbulent, characteristics of flow field have great influence on the valves working performance.Main work of this paper is numerical calculation and simulation of cone valve inner runner flow field inside hydraulic hammer. First make a 3D modeling for cone valve using Pro/E, by fluent this paper analyses and discusses the distribution of hydraulic cone valve internal flow field including flow velocity field, pressure field and flow, etc when the cone valve core taper angle is 30°, the gap is 0.5 mm, and inlet velocity is different, analyses position and strength of the vortex, and finds out the main reason for energy consumption.The results of the study show that by the optimal design of the cone valve seat, the density degree of the flow and the size of the vortex is reduced, the energy loss is reduced, negative pressure zone also changes, the noise is reduced and the energy utilization is improved.

2D and 3D Unsteady Flow in Squirrel-Cage Centrifugal Fan and Aeroacoustic Behavior

2006 ◽  
Author(s):  
M. Younsi ◽  
F. Bakir ◽  
S. Kouidri ◽  
R. Rey
Keyword(s):  
Unsteady Flow ◽  
Numerical Models ◽  
Pressure Fluctuations ◽  
Internal Flow ◽  
Navier Stokes ◽  
Computational Domain ◽  
Centrifugal Fan ◽  
Geometry Modeling ◽  
3D Unsteady Flow ◽  
2D And 3D

The objective of this paper is the study and the analysis of the complex phenomena related to the internal flow in a centrifugal fan, using Computational Fluid Dynamics (CFD) tools, completed with experimental investigation in order to validate the used numerical models. The CFD analysis concerns 2D and 3D unsteady flow. The studied phenomena are the interactions and unsteadiness induced by the motion of the rotating blades relatively to the volute and their impact on the aeroacoustic behavior of the fan. Thus, 3D and 2D unsteady calculations using Unsteady Reynolds Averaged Navier Stokes (URANS) approach has been applied on a hybrid mesh grid whose refinement has been studied and adapted to the flow morphology. Turbulence has been modeled with the k-ω-Shear Stress Model (SST) model. The computational domain has been divided into two zones, a rotating zone including the impeller and stationary zone including the volute. A sliding mesh technique has been applied to the interfaces in order to allow the unsteady interactions between the two zones. The overall performances predicted by the computations have been validated at different flow rate. For each geometry modeling (2D and 3D), the unsteady part of the study is illustrated by analyzing the pressure fluctuations on different points from the lateral surface of the volute. The analysis of the wake generated by the rotation of the blower shows that the volute tongue is the main zone of unsteadiness and flow perturbations. In order to predict the acoustic pressures, the unsteady flow field variables provided by the CFD calculations have been used as inputs in the Ffowks Williams-Hawkings equations.

Analysis of Concentric Canister Wall Roughness Effect on Jet Flow Based on Fluid Dynamics

2012 ◽  
Vol 252 ◽  
pp. 3-8
Author(s):  
Yun Shan Bai ◽  
Yi Jiang ◽  
Dong Mo Zhou
Keyword(s):  
Flow Field ◽  
Influence Factor ◽  
Great Influence ◽  
Internal Flow ◽  
Rough Wall ◽  
Concentric Cylinder ◽  
Smooth Flow ◽  
Practical Engineering ◽  
Mesh Update ◽  
Main Factor

Adopting concentric canister launchers (CCL), high temperature and high pressure environment of CCL is unfavorable for the missile launch. In addition to the gap between internal canister and external canister, injecting water for cooling are the main factor of impact the canister flow field, CCL’s rough wall is also a very important influence factor. In this paper, under the two working conditions of rough wall and smooth wall, use dynamic layering manner of moving mesh update method to simulate concentric canister missile launch process. The results reveal that rough wall has a great influence for pressure of concentric canister internal flow field, but the least influence for temperature. In practical engineering applications, need smooth surface material for smooth flow field exhaust when manufacturing concentric cylinder, but the non-concentric canister manufacturing of missile cold-launch canister, retain the rough wall can increase the pressure of the missile launch, this is conducive to missile launch, and also saves manufacturing costs, reduces processing procedures.

Flow Field Analysis and Structure Optimization of Water Hydraulic Poppet Valve Based on the CFD

2013 ◽  
Vol 791-793 ◽  
pp. 734-737 ◽  
Author(s):  
Qiu Xia ◽  
Xiang Pan Guang
Keyword(s):  
Flow Field ◽  
Simulation Analysis ◽  
Internal Flow ◽  
Turbulent Energy ◽  
Field Analysis ◽  
Value Differences ◽  
Poppet Valve ◽  
Traditional Structure ◽  
Fluent Software ◽  
Water Hydraulic

This paper builds two water hydraulic poppet valve models which are of different structure, and simulation analysis used by FLUENT software on it’s internal flow field. The analysis results show that, after improving the structure of water hydraulic poppet valve, import and export pressure value differences decreased, effectively restrains the generation of cavitation, reduces the vibration amplitude and turn down noise, reduces loss of turbulent energy, the overall performance is superior to the traditional structure.

scholarly journals Numerical Investigation of Flow Field and Energy Loss in a Centrifugal Pump as Turbine

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jingze Li ◽  
Dongrong Meng ◽  
Xun Qiao
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Energy Loss ◽  
Entropy Generation ◽  
Flow Separation ◽  
Guide Vane ◽  
Great Influence ◽  
Internal Flow ◽  
Asymmetric Structure ◽  
Centrifugal Pumps

Centrifugal pumps as turbine (PAT) are widely used in petrochemical and water conservancy industries. The research on the internal flow field and energy loss of PAT is of great significance to improve the performance and efficiency of PAT. In this paper, experimental and numerical simulation methods are used to study the energy loss and flow field. The results show that the numerical simulation method can accurately simulate the internal flow field of PAT. And the entropy generation theory is applied to visualize the internal energy loss of PAT through the comparison of total pressure loss and entropy generation. The highest energy loss among PAT components is the guide vane. The loss in the guide vane is mainly caused by the flow separation caused by the wake of the guide vane and the asymmetric structure of the volute. The losses in the impeller are mainly due to flow separation and wake. Besides, the unsteady simulation results show that rotor-stator interaction has a great influence on the gap between the impeller and the guide vane. The research results provide a reference for the design of the PAT. This study is beneficial to studying the dynamic and static interference and PAT vibration to improve the stability of the PAT.

scholarly journals Analysis of Unsteady Pressure Fluctuation in a Semi-Open Cutting Pump

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3657
Author(s):  
Weidong Cao ◽  
Jiayu Mao ◽  
Wei Li
Keyword(s):  
Flow Rate ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Lower Plate ◽  
Pressure Distributions ◽  
Axial Forces ◽  
Blade Frequency

In order to understand the pressure fluctuation characteristics of a semi-open cutting pump, the three-dimensional unsteady flow fields were calculated. External and internal flow characteristics of four schemes with different relative angles between the rotary cutter and the impeller were studied. The pressure fluctuations in the lower plate, the upper plate, the clearance between the rotary cutter and the fixed cutter, the first section in volute and nearby parts of the tongue were all analyzed, which are all the places that pressure distributions are greatly affected by the static and dynamic interaction, and at the same time, the force on the impeller was also analyzed. The results show that the fluctuations at different positions change periodically; the main frequency is blade frequency. The amplitude of pressure fluctuation decreases from near the rotating part to far away, from near the tongue to far from the tongue. Due to the influence of both impeller and rotary cutter, the pressure fluctuation on the lower plate is the largest. The pressure fluctuation is affected by flow rate, the larger the flow rate, the greater the pressure fluctuation. The radial and axial forces of the impeller change periodically with time, and the number of wave peaks and wave valleys is the same as the number of blades.

Numerical Simulation on Effect of Volute Width on Performance of a Centrifugal Fan

2012 ◽  
Vol 538-541 ◽  
pp. 686-689
Author(s):  
Yu Kun Lv ◽  
Bao Jun Song ◽  
Tong Chang Lu
Keyword(s):  
Numerical Simulation ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Design Flow ◽  
Centrifugal Fan ◽  
Contrastive Analysis ◽  
Optimization Principle ◽  
And Performance ◽  
Performance Results ◽  
Full Pressure

Taking the G4-73№8D centrifugal fan as research object and utilizing the software of NUMECA to simulate flow fields of volute with different widths, the parameters of width are optimized through contrastive analysis of the effects on internal flow characteristics and performance. Results show that the optimized scheme can improve the uniformity of internal flow field, full pressure and efficiency seperatly increase by 0.52% and 0.48% under the design flow. For the needs of variable fan load operation, this paper puts forward the optimization principle of width parameter.

Design considerations for the volutes of centrifugal fans and compressors

1999 ◽  
Vol 213 (4) ◽  
pp. 401-410 ◽  
Author(s):  
D Pan ◽  
A Whitfield ◽  
M Wilson
Keyword(s):  
Three Dimensional ◽  
Flow Distribution ◽  
Internal Flow ◽  
Area Ratio ◽  
Design Flow ◽  
Centrifugal Fan ◽  
Flow Conditions ◽  
Design Considerations ◽  
Centrifugal Fans ◽  
Computational Fluid Dynamics Cfd

The initial conceptual design of centrifugal fan and compressor volutes is considered and extended to accommodate overhung volute designs often used in process and turbocharger compressors. The initial passage design is then developed through the application of a commercial computational fluid dynamics (CFD) code.’ Based on the experimental data of a turbocharger compressor volute, three-dimensional, compressible, steady flow computations were carried out for alternative volute designs. Detailed internal flow data in both a conventional and a modified volute design, at both design and off-design flow conditions, are presented. The design investigation showed that enlarging the flow passage area near the tongue region, but without changing the exit-inlet area ratio of the volute, led to an improvement in the internal flow distribution at off-design flow conditions.

The Optimal Research on Impeller Central Location of Centrifugal Fan

2014 ◽  
Vol 668-669 ◽  
pp. 729-732
Author(s):  
Yu Kun Lv ◽  
Bo Zhang ◽  
Bo Cheng
Keyword(s):  
Flow Field ◽  
Static Pressure ◽  
Internal Flow ◽  
Flow Fields ◽  
Centrifugal Fan ◽  
Contrastive Analysis ◽  
Location Optimization ◽  
Central Location ◽  
Center Location ◽  
Variable Condition

Taking the G4-73№8D centrifugal fan as research object and utilizing the software of NUMECA to simulate flow fields of volutes with different radial relative positions, the optimum central location of the fan impeller was obtained. The contrastive analysis of internal flow field which of the original and impeller center location optimization fan was under the rated and variable condition, showed that the optimized fan enhanced impeller and volute casing radial adaptive and the efficiency and export static pressure of optimized fan were improved.

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