Numerical Modeling and Simulation of a Volumetric Resistance Blower Using Porous Rotor

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Sanket Girhe ◽  
Ruander Cardenas ◽  
Mark MacDonald ◽  
Anandaroop Bhattacharya
Keyword(s):  
Acoustic Noise ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Sliding Mesh ◽  
Modeling Methodology ◽  
Output Flow ◽  
Different Types ◽  
New Type ◽  
Numerical Modeling And Simulation

Abstract This paper presents an experimentally validated modeling methodology for a new type of blower design known as volumetric resistance blower (VRB). It replaces the traditional centrifugal blower fan blades with a continuous porous medium disk and has been reported to be capable of providing a lower acoustic noise for the same output flow compared to a traditional blower. A three-dimensional transient numerical model of VRB is developed which incorporates the movement of a porous rotor using experimentally determined foam parameters to characterize the porous drag effect and a sliding mesh to simulate the rotation effect. The numerical results are validated with experimentally determined fan curve over broad range of operating conditions. The effect of the foam resistance parameters on the flow characteristics is investigated which serves the rationale for the optimization of these parameters. The model is used to study the sensitivity of the VRB performance to foam parameters using different types of commercially available open-cell reticulated foam.

PIV Measurements in Diffuser of the Radial Pump

2015 ◽  
Author(s):  
Sung Yong Jung ◽  
Young Uk Min ◽  
Kyung Lok Lee
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Internal Flows ◽  
Piv Measurements ◽  
Image Velocimetry ◽  
Acquisition Device ◽  
Field Information ◽  
Radial Pump

The performance characteristics of the radial pump commonly used as a multistage (8 or 10 stage) pump have been investigated experimentally. Due to the complex three-dimensional geometries, the hydraulic performance of multistage pumps is closely related to the internal flows in diffuser and return vanes. In order to investigate the flow characteristics in these regions by Particle Image Velocimetry (PIV) technique, a transparent pump is designed. A 532 nm continuous laser and a high-speed camera are used as a light source and an image acquisition device, respectively. The velocity field information in a diffuser of the radial pump is successfully obtained by two-dimensional PIV measurements at various operating conditions.

Three-Dimensional Liquid Sloshing Numerical Analysis on a New Designed Tank Container

2019 ◽  
Author(s):  
Wenjun Yue ◽  
Xu Chen
Keyword(s):  
Fluid Flow ◽  
Carrying Capacity ◽  
Impact Force ◽  
Three Dimensional ◽  
Economic Benefits ◽  
Cylindrical Vessel ◽  
Filling Ratio ◽  
Operating Conditions ◽  
New Type ◽  
Maximum Impact Force

Abstract Based on the conventional tank container which has a cylindrical vessel, a new structure of tank container was designed to improve the carrying capacity of the tank. Fluid flow inside the new tank container under different operating conditions (liquid filling ratio K, braking deceleration a, filling medium, no baffle and with baffles) was studied. A volume-of-fluid (VOF) method and a k-epsilon (k-ε) turbulence model were used to simulate the fluid flow. Results showed that all the factors studied in this work had an influence on the tank. The maximum impact force increased with the increasing of a and K. A clear linear positive correlation was found between the maximum impact force and braking deceleration. Besides, the maximum impact force had a relationship with the density of medium. Compared with the conventional tank container, the carrying capacity of the new type tank container increases by 11.8%, which means the new type tank container has better economic benefits.

Numerical Simulation of Heat Transfer Characteristics of Dimpled Plate

2012 ◽  
Vol 170-173 ◽  
pp. 2686-2692
Author(s):  
Chang Fa Ji ◽  
Xiao Bing Liu ◽  
Rui Liu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Exchanger ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Plate Heat Exchanger ◽  
Plate Heat ◽  
Heat Transfer Efficiency ◽  
New Type ◽  
The Impact

Designed a new type of plate heat exchanger-dimpled plate heat exchanger, then conducted a three-dimensional numerical simulation on flow, heat transfer and resistance characteristics of 15 kinds of different sizes dimpled plate heat exchangers by Fluent software，obtains the impact of the dimples geometric parameters such as dimple diameter, dimple spacing, dimple height on the heat transfer and flow characteristics. The results show that in different Reynolds number, dimple diameter, dimple spacing and dimple height on the effect of the dimple plate heat transfer efficiency is quite similar, and the impact becomes increasingly evident with the Reynolds numbers increasing. The combined effect of plate heat exchanger is best when dimple diameter, dimple spacing, dimple height are separately 12mm, 21mm, 4mm in the 15 kinds of different combination dimpled plates.

Non-Equilibrium Turbulence Modelling for Compressor Corner Separation Flows

2021 ◽  
Author(s):  
Wei Sun
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Operating Conditions ◽  
Suction Surface ◽  
Physical Reason ◽  
Corner Separation ◽  
Separation Flows ◽  
Non Equilibrium

Abstract Corner separation is one type of the three-dimensional (3D) separated flows which is commonly observed at the junction of the blade suction surface and endwall of an axial compressor. The commonly used Reynolds-Averaged Navier-Stokes (RANS) turbulence models, namely Spalart-Allmaras (SA) and Menter’s Shear Stress Transport (SST) models, have been found to overpredict the size of corner separation. The physical reason is partly attributed to the underestimation of turbulence mixing between the mainstream flow and the endwall boundary-layer flow. This makes the endwall boundary layer unable to withstand the bulk adverse pressure gradients, and in turn leads to its premature separation from the endwall surface during its migration towards the endwall/blade suction surface corner. The endwall flow characteristics within the compressor stator cascade are then studied to facilitate understanding the physical mechanisms that drive the formation of 3D flow structures, and the physical reasons that lead to RANS modelling uncertainties. It is found that the insufficient near-wall boundary layer mixing is partly due to the failure of both SA and SST models to reasonably model the non-equilibrium turbulence behaviors inside the endwall boundary layer, which is caused by the boundary layer skewness. Based on the understanding of the skew-induced turbulence characteristics and its effect on mixing, a detailed effort is presented towards the physical-based modelling of the skew-induced non-equilibrium wall-bounded turbulence. The source terms in the SA and SST models that control mixing are identified and modified, in order to enhance mixing and strengthen the endwall boundary layer. The improved turbulence models are then validated against the compressor corner separation flows under various operating conditions to prove that the location and extent of the corner separation are more realistically predicted.

scholarly journals Sensitivity analysis of nuclear main pump annular casing tongue blend

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401770659 ◽  
Author(s):  
Xiaorui Cheng ◽  
Wenrui Bao ◽  
Li Fu ◽  
Xiaoting Ye
Keyword(s):  
Kinetic Energy ◽  
Numerical Simulations ◽  
Turbulent Kinetic Energy ◽  
Stokes Equations ◽  
Flow Instability ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Simple Algorithm ◽  
Operating Conditions ◽  
Navier Stokes

Based on the Reynolds-averaged Navier–Stokes equations of relative coordinates and the RNG k-ε turbulence model, using our SIMPLE algorithm, we performed numerical simulations for an AP1000 nuclear main pump model with water as the medium. By changing the size of the tongue blend in the annular casing, seven different schemes were designed. Three-dimensional numerical simulations were conducted for the flow within the pump under various settings, and the flow characteristics of the annular casing using different tongue blends were obtained. The results show that for different operating conditions, there is a specific tongue blend that optimizes pump performance. Based on the calculation results, a larger tongue blend leads to a larger flow rate. Off-design conditions caused flow instability, which in turn caused the tongue blend to have a certain impact on the performance of the impeller. However, the performance of the pump was not primarily affected by changes in the impeller performance, but was instead affected by the performance of the annular casing, which was itself affected by tongue blend. When changing the tongue blend, the change in static pressure and total pressure of the annular casing was larger under the condition of 0.6 Qd and was smaller under the conditions of 1.0 Qd and 1.4 Qd. The turbulent kinetic energy in the annular casing changed mainly in the tongue impact zone and outlet diffuser under the condition of 1.0 Qd; furthermore, the turbulent kinetic energy in the whole of the annular casing demonstrated significant changes under the conditions of 0.6 Qd and 1.4 Qd.

Flow Characteristics in a Channel With Corona Wind Generator

2010 ◽  
Author(s):  
J. Zhang ◽  
F. C. Lai
Keyword(s):  
Volume Flow Rate ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Square Channel ◽  
Wind Generator ◽  
Numerical Predictions ◽  
Wide Range ◽  
Flow Transport ◽  
Corona Wind

Electrohydrodynamically induced flows have shown great potential for many engineering applications. Previous studies have revealed that a corona wind generator can be used to enhance flow transport in a channel. In this study, a corona wind generator with emitting wire electrodes flush mounted on the channel walls is considered for a wide range of operating conditions. Specifically, three configurations of the generator (with 4, 12, and 28 pins of emitting electrodes) are evaluated for their effectiveness in delivering the air flow. To investigate the flow characteristics inside a square channel, three-dimensional governing equations for electric and flow fields are numerically solved. The corona current is first measured experimentally and used in the numerical calculations. Numerical predictions on the velocity profile of corona-induced air flows as well as the volume flow rate delivered have been successfully verified by experimental results.

Metallic Clusters With Ligands and Polyhedral Core

2021 ◽  
pp. 147-170
Keyword(s):  
Three Dimensional ◽  
Metallic Clusters ◽  
Higher Dimensional ◽  
Different Types ◽  
New Type ◽  
Cluster Geometry ◽  
Cluster A

The geometry of clusters with ligands and a polyhedral frame is considered by the methods of studying the geometry of higher-dimensional polytopes, developed in the author's monograph. It is shown that these methods allow us to establish important details of cluster geometry, which elude analysis based on the representations of three-dimensional geometry. It is established that the well-known Kuban cluster is a 4-cross-polytope, which allows different variants of the Kuban cluster. A cluster of gold with a tetrahedral backbone is a 5-cross-polytope. The cluster tetra anion of cobalt is a polytope of dimension 5 of a new type. Different types of ligands limit the cobalt skeleton from above and below.

scholarly journals Mathematical modeling of stress-strain state of the nodal joint of wooden beams

2021 ◽  
Vol 2131 (3) ◽  
pp. 032088
Author(s):  
M S Sergeev ◽  
M V Lukin ◽  
A A Strekalkin ◽  
S I Roshchina
Keyword(s):  
Cross Section ◽  
Sharp Increase ◽  
Static Load ◽  
Numerical Study ◽  
Solid Wood ◽  
Operating Conditions ◽  
Aluminum Composite ◽  
Different Types ◽  
New Type ◽  
Wooden Structures

Abstract The article presents a study of the joint of wooden beams on a new type of aluminum composite connector. For the numerical experiment, beams with a cross-section of 150x220(h) mm made of solid wood were selected. The beams were connected at the same level in a perpendicular direction to each other. The connecting connectors were made of two types of alloys: 7075 T6 and 6061 T6. The experiment was carried out until the joint was completely destroyed under static load. The elastic operation of the node for different types of connectors under study was maintained until the load of 50… 70 kN, after which there was a sharp increase in the deformations of the beams. Conducting a numerical study of the elements of wooden structures made it possible to predict their behavior most accurately in real operating conditions.

scholarly journals Numerical Research of Pump-as-Turbine Performance with Synergy Analysis

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1031
Author(s):  
Zheng Cao ◽  
Jianqiang Deng ◽  
Linkun Zhao ◽  
Lin Lu
Keyword(s):  
Flow Rate ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Operating Conditions ◽  
Field Analysis ◽  
Sensitivity Index ◽  
Computational Fluid Dynamics Cfd ◽  
Numerical Research ◽  
Hydraulic Devices

The wide use of pumps and turbines has significant value in energy conservation and utilization. In this work, a three-dimensional Computational Fluid Dynamics (CFD) model and a one-dimensional theoretical model of a Pump as Turbine (PAT) were established. On this basis, the correlation between pressure and velocity was quantitatively investigated by a proposed sensitivity index (SPV). A synergy field analysis was then applied to evaluate the flow characteristics of a pump and PAT, providing a perspective from the mechanism of the energy transfer enhancement for hydraulic devices. Moreover, the hydraulic and synergy performances of PAT were studied under various operating conditions. The results show that the minimum SPV is obtained in the impeller. With increasing flow rate, the SPV of the PAT generally increases, and the synergy angle of the impeller surface increases as well. A strong disordered synergy field is observed in regions of the blade leading edge, trailing edge, and volute tongue. The variations in efficiency and head with flow rate showed similar trends, respectively, with the synergy angle of the outlet and the mid-plane. This study provides an analytical method for quantitative evaluation of flow synergy characteristics, and it supplies a basis for further design improvement of the pump and PAT.

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