scholarly journals A New Method for Rapid Optimization Design of a Subsonic Tandem Blade

2020 ◽  
Vol 10 (24) ◽  
pp. 8802
Author(s):  
Yuan Tao ◽  
Xianjun Yu ◽  
Baojie Liu
Keyword(s):  
Optimization Design ◽  
Fluid Dynamic ◽  
Flow Characteristics ◽  
New Method ◽  
Transonic Compressor ◽  
Controlled Diffusion ◽  
Aerodynamic Interaction ◽  
Modification Method ◽  
Computation Fluid Dynamic ◽  
Inflow Conditions

Tandem blade technology has been developed for years due to its capacity to bear higher aerodynamics than conventional configurations. Even so, there is still the tough problem of how to design tandem blades effectively and further improve blade performance. This paper tries to further understand the flow characteristics of tandem blades in order to present a new method of designing them under subsonic inflow conditions. Firstly, efforts were made to reveal the aerodynamic interaction between the forward blade (FB) and the aft blade (AB). Secondly, considering this aerodynamic interaction, the design principles and the camber line modification method were put forward, with which typical controlled diffusion airfoil (CD airfoil) isentropic Mach number distributions can be achieved for both FB and AB. Lastly, the optimizations were conducted on a 2D tandem blade and a transonic compressor with a tandem blade, respectively. The computation fluid dynamic (CFD) results show that the optimized tandem blade achieves a significant improvement for both 2D blade performance and transonic compressor characteristics at low speeds.

Study on Global Aerodynamic Shape Optimization of Transonic Compressor Blade

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Yanhui Duan ◽  
Zhaolin Fan ◽  
Wenhua Wu ◽  
Ti Chen
Keyword(s):  
Shape Optimization ◽  
Optimization Design ◽  
Fluid Dynamic ◽  
Thickness Distribution ◽  
Pressure Ratio ◽  
Compressor Blade ◽  
Aerodynamic Shape Optimization ◽  
Aerodynamic Shape ◽  
Transonic Compressor ◽  
Total Pressure Ratio

AbstractIn this paper, global optimization design of a transonic compressor 3D blade (Rotor 37) has been carried out by a self-developed aerodynamic shape optimization (ASO) platform based on improved parallel synchronous particle swarm optimization (PSPSO). To improve the performance of PSPSO, coefficient of variation (COV) based attenuation method with new parameters is proposed and then validated by optimization tests. Flow field of blade is calculated by an in-house computational fluid dynamic (CFD) code called PMB3D-Turbo, which is validated by Rotor 37. Choosing Rotor 37 as the case, optimization object is to maximize the peak adiabatic efficiency, meanwhile constraining mass flow and total pressure ratio. The solutions show that, the ASO platform is effective to transonic compressor blade and variations of thickness distribution near the trailing edge can help improve the adiabatic efficiency of a transonic compressor blade.

The Wall Shear Stress Vector: Methods for Characterising Truly Disturbed Flow

2012 ◽  
Author(s):  
Véronique Peiffer ◽  
Peter D. Weinberg ◽  
Spencer J. Sherwin
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Fluid Dynamic ◽  
Flow Characteristics ◽  
New Method ◽  
Molecular Signaling ◽  
Stress Vector ◽  
Cfd Simulations ◽  
Disturbed Flow ◽  
Wall Shear

Haemodynamic stresses acting on the arterial wall may play an important role in the initiation and development of atherosclerosis, and in particular are likely to explain its focal occurrence. Computational fluid dynamic (CFD) simulations of blood flow in arteries have been widely used to investigate this relation and a variety of metrics have been derived to link flow characteristics with lesion prevalence [1]. Although the initial focus was on the magnitude of the time-averaged wall shear stress (TAWSS), an oscillatory shear index (OSI) was subsequently introduced “to describe the shear stress acting in directions other than the direction of the temporal mean shear stress vector” [2]. Biological evidence suggests that flow without a definite direction, in contrast to shear with a clear direction (whether resulting from steady or pulsatile flow), causes sustained molecular signaling of pro-inflammatory and proliferative pathways [3]. Although the OSI has frequently been used to quantify the extent of disturbed flow, we emphasise that no singular metric can fully characterise the flow environment; in particular, we and other research groups [4] note that OSI and other similar metrics are unable to distinguish between simple uniaxial flows (which can be purely forward flowing or reversing) and multi-directional flows, which we term “truly disturbed”. We propose a new method that has this potential, and which complements existing metrics. The new method may help investigations of the importance of flow directionality.

scholarly journals Effects of Selection of Inlet Perturbations, Multiphase and Turbulence Equations on Slug Flow Characteristics Using Altair® AcuSolve™

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2152
Author(s):  
Mohammad Sobir Abdul Basith ◽  
Nabihah Sallih ◽  
William Pao King Soon ◽  
Shinji Thomas Shibano ◽  
Ramesh Singh ◽  
...  
Keyword(s):  
Level Set ◽  
Slug Flow ◽  
Fluid Dynamic ◽  
Flow Characteristics ◽  
Convective Transport ◽  
Experimental Result ◽  
Internal Boundary ◽  
Published Data ◽  
Level Set Function ◽  
Selection Of

Selection of inlet perturbations, multiphase equations, and the turbulence equation may affect the development of slug flow using computational fluid dynamic simulation tools. The inlet perturbation, such as sinusoidal and random perturbations, play an essential role in inducing slug formation. Multiphase equations such as volume of fluid and level set methods are used to track and capture the gas-liquid immiscible interface. Similarly, turbulence equations such as Spalart Allmaras (SA), Detached Eddy Simulations (DES), k-omega, and k-epsilon can be used to predict the evolution of turbulence within the flow. At present, no direct comparison is available in the literature on the selection of (i) types of inlet perturbations, (ii) the choice of multiphase equations, and (iii) the turbulence equation on the development of slug flow using the Altair computational package. This article aims to compare the effects of the selection of inlet perturbations, multiphase models and turbulence equations on slug flow characteristics using Altair® AcuSolve™. The findings by Altair® simulation were compared to published experimental data and simulation works using ANSYS and STAR-CCM+. The slug flow characteristics of interest include slug morphology, a body length-to-diameter ratio, velocity, frequency, and pressure gradient. It was found that the slug flow could be developed for all combinations of settings. Although level set approach in Altair® can track fluid motion successfully, it has a limitation in modelling the convective transport of the multiphase mixture well, unlike ANSYS and STAR-CCM+. Compared to the standard level set method, the coupling of back-and-forth error compensation and correction with the level set function helps to capture the internal boundary more accurately by reducing errors caused by numerical diffusion in the transport of the level set. It was revealed that the Spalart Allmaras turbulence equation could mimic published experimental result better than DES as it produced the closest slug translational velocity. Since the frequency of the slugs for the developed models showed a good agreement with the published data, the models could be sufficient for the investigation of fluid-structure interaction.

scholarly journals Bayesian Optimization Design of Inlet Volute for Supercritical Carbon Dioxide Radial-Flow Turbine

Machines ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 218
Author(s):  
Chao Bian ◽  
Shaojie Zhang ◽  
Jinguang Yang ◽  
Haitao Liu ◽  
Feng Zhao ◽  
...  
Keyword(s):  
Optimization Design ◽  
Radial Flow ◽  
Flow Characteristics ◽  
Bayesian Optimization ◽  
Working Fluid ◽  
Cross Sectional ◽  
Pressure Loss Coefficient ◽  
Flow Capacity ◽  
Cycle Efficiency ◽  
Total Pressure Loss Coefficient

The radial-flow turbine, a key component of the supercritical CO2 (S-CO2) Brayton cycle, has a significant impact on the cycle efficiency. The inlet volute is an important flow component that introduces working fluid into the centripetal turbine. In-depth research on it will help improve the performance of the turbine and the entire cycle. This article aims to improve the volute flow capacity by optimizing the cross-sectional geometry of the volute, thereby improving the volute performance, both at design and non-design points. The Gaussian process surrogate model based parameter sensitivity analysis is first conducted, and then the optimization process is implemented by Bayesian optimization (BO) wherein the acquisition function is used to query optimal design. The results show that the optimized volute has better and more uniform flow characteristics at design and non-design points. It has a smoother off-design conditions performance curve. The total pressure loss coefficient at the design point of the optimized volute is reduced by 33.26%, and the flow deformation is reduced by 54.55%.

scholarly journals Effect of Tip Clearance on Helico-Axial Flow Pump Performance at Off-Design Case

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1653
Author(s):  
Nengqi Kan ◽  
Zongku Liu ◽  
Guangtai Shi ◽  
Xiaobing Liu
Keyword(s):  
Optimization Design ◽  
Flow Characteristics ◽  
Axial Flow ◽  
Leading Edge ◽  
Tip Clearance ◽  
Hydraulic Loss ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Axial Flow Pump ◽  
Flow Pump

To reveal the effect of tip clearance on the flow behaviors and pressurization performance of a helico-axial flow pump, the standard k-ε turbulence model is employed to simulate the flow characteristics in the self-developed helico-axial flow pump. The pressure, streamlines and turbulent kinetic energy in a helico-axial flow pump are analyzed. Results show that the tip leakage flow (TLF) forms a tip-separation vortex (TSV) when it enters the tip clearance and forms a tip-leakage vortex (TLV) when it leaves the tip clearance. As the blade tip clearance increases, the TLV moves along the blade from the leading edge (LE) to trailing edge (TE). At the same time, the entrainment between the TLV and the main flow deteriorates the flow pattern in the pump and causes great hydraulic loss. In addition, the existence of tip clearance also increases the possibility of TLV cavitation and has a great effect on the pressurization performance of the helico-axial flow pump. The research results provide the theoretical basis for the structural optimization design of the helico-axial flow pump.

Computation Fluid Dynamic Modeling of a Proposed Influent Pump Station

2006 ◽  
Vol 2006 (5) ◽  
pp. 7094-7114 ◽  
Author(s):  
Edward Wicklein ◽  
Charles Sweeney ◽  
Constantino Senon ◽  
Doug Hattersley ◽  
Brian Schultz ◽  
...  
Keyword(s):  
Dynamic Modeling ◽  
Fluid Dynamic ◽  
Pump Station ◽  
Computation Fluid Dynamic

Optimization Design of Self-Balacing Torsion Bar Diameter

2011 ◽  
Vol 308-310 ◽  
pp. 2486-2489
Author(s):  
Zhi Qi Huang
Keyword(s):  
Optimization Model ◽  
Optimization Design ◽  
Ant Colony Algorithm ◽  
The Self ◽  
Ant Colony ◽  
New Method ◽  
C Language ◽  
Torsion Bar ◽  
Bar Diameter ◽  
Theoretical Results

The thesis builds the optimization model for the self-balacing torsion bar, On the basis of the Ant Colony Algorithm, designs the Ant Colony Algorithm procedure using C Language and optimizes torsion bar diameter. Results show the Ant Colony Algorithm is feasible and provides a new method choosing torsion bar diameter. The max difference value is 1.12% between optimizing results and theoretical results.

Performance of Perforated Wall for the Conditioning of the Flow in an Ocean Basin

2008 ◽  
Author(s):  
Alexandre T. P. Alho ◽  
Sergio H. Sphaier ◽  
Carlos A. Levi Conceic¸a˜o ◽  
Paulo de Tarso T. Esperanc¸a
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Perforated Plate ◽  
Flow Characteristics ◽  
Ocean Basin ◽  
Main Flow ◽  
Generation System ◽  
Current Generation ◽  
Hydraulic Design ◽  
Inflow Conditions

This paper discusses the investigations conducted to develop the hydraulic design of the flow conditioner of the current generation system of LabOceano. The performance of different flow conditioner configurations were numerically investigated by means of computational fluid dynamics techniques. The numerical results were validated against experimental data, showing a good performance of the numerical model in predicting the main flow characteristics. It was observed that undesirable high angles of incidence of the flow occur upstream of the flow conditioner, indicating that the culvert geometry is not of much help to contribute to the conditioning of the flow. However, the results demonstrate that, in spite of such an adverse inflow conditions, the classical solution based on the perforated plate concept works very well.

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