Investigation of an innovative non-free vortex aerodynamic procedure to design a single-stage transonic compressor

2017 ◽  
Vol 232 (11) ◽  
pp. 2132-2143 ◽  
Author(s):  
A Shahsavari ◽  
M Nili-Ahmadabadi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Stokes Equations ◽  
Design Method ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Rotor Blades ◽  
Meridional Plane ◽  
Transonic Compressor ◽  
Performance Map

This paper presents an innovative design method for a transonic compressor based on the radial equilibrium theory by means of increasing blade loading. Firstly, the rotor blade of a transonic compressor is redesigned based on the constant spanwise de-Haller number and diffusion. The design method leads to an unconventional increased axial velocity distribution in tip section, which originates from non-uniform enthalpy distribution assumption. A code is applied to extract the compressor meridional plane and blade-to-blade geometry containing rotor and stator in order to design the blade three-dimensional view. A structured grid is generated for the numerical domain of fluid. Finer grids are used for the regions near walls to capture the boundary layer effects and behavior. Reynolds-averaged Navier–Stokes equations are solved by finite volume method for rotating zones (rotor) and stationary zones (stator). The experimental data, available for the performance map of NASA Rotor67, is used to validate the results of the current simulations. Then, the capability of the design method is validated by computational fluid dynamics that is capable of predicting the performance map. The numerical results of the new geometry by representing 11% improvement in efficiency and 19% in total pressure ratio verify the new method advantages. The computational fluid dynamics results also show that the newly designed rotor blades due to a higher velocity in the tip section have a special capacity to increase the loading without any separation. The mass flow reduction is observed in the new geometry, which could be easily improved by changing stagger angle.

Direct Design of Ducts

2003 ◽  
Vol 125 (1) ◽  
pp. 158-165 ◽  
Author(s):  
A. Ashrafizadeh ◽  
G. D. Raithby ◽  
G. D. Stubley
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Pressure Distribution ◽  
Design Method ◽  
Three Dimensional ◽  
Viscous Flows ◽  
Simple Extension ◽  
Two Dimensional ◽  
Direct Design ◽  
Dependent Variables

This paper describes a method for calculating the shape of duct that leads to a prescribed pressure distribution on the duct walls. The proposed design method is computationally inexpensive, robust, and a simple extension of existing computational fluid dynamics methods; it permits the duct shape to be directly calculated by including the coordinates that define the shape of the duct wall as dependent variables in the formulation. This “direct design method” is presented by application to two-dimensional ideal flow in ducts. The same method applies to many problems in thermofluids, including the design of boundary shapes for three-dimensional internal and external viscous flows.

scholarly journals A zonal approach for estimating pressure ratio at compressor extreme off-design conditions

2018 ◽  
Vol 20 (4) ◽  
pp. 393-404 ◽  
Author(s):  
José Galindo ◽  
Roberto Navarro ◽  
Luis Miguel García-Cuevas ◽  
Daniel Tarí ◽  
Hadi Tartoussi ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Pressure Ratio ◽  
Internal Combustion ◽  
Operating Conditions ◽  
Combustion Engines ◽  
One Dimensional ◽  
Performance Map

Zero-dimensional/one-dimensional computational fluid dynamics codes are used to simulate the performance of complete internal combustion engines. In such codes, the operation of a turbocharger compressor is usually addressed employing its performance map. However, simulation of engine transients may drive the compressor to work at operating conditions outside the region provided by the manufacturer map. Therefore, a method is required to extrapolate the performance map to extended off-design conditions. This work examines several extrapolating methods at the different off-design regions, namely, low-pressure ratio zone, low-speed zone and high-speed zone. The accuracy of the methods is assessed with the aid of compressor extreme off-design measurements. In this way, the best method is selected for each region and the manufacturer map is used in design conditions, resulting in a zonal extrapolating approach aiming to preserve accuracy. The transitions between extrapolated zones are corrected, avoiding discontinuities and instabilities.

Multi-Objective Optimization of a High Specific Speed Centrifugal Volute Pump Using Three-Dimensional Inverse Design Coupled With Computational Fluid Dynamics Simulations

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Luying Zhang ◽  
Gabriel Davila ◽  
Mehrdad Zangeneh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Design Method ◽  
Three Dimensional ◽  
Inverse Design ◽  
Computational Time ◽  
Specific Speed ◽  
Meridional Shape ◽  
Inverse Design Method ◽  
Blade Geometry

Abstract This paper presents three different multiobjective optimization strategies for a high specific speed centrifugal volute pump design. The objectives of the optimization consist of maximizing the efficiency and minimizing the cavitation while maintaining the Euler head. The first two optimization strategies use a three-dimensional (3D) inverse design method to parametrize the blade geometry. Both meridional shape and 3D blade geometry are changed during the optimization. In the first approach, design of experiment (DOE) method is used and the pump efficiency is obtained from computational fluid dynamics (CFD) simulations, while cavitation is evaluated by using minimum pressure on blade surface predicted by 3D inverse design method. The design matrix is then used to create a surrogate model where optimization is run to find the best tradeoff between cavitation and efficiency. This optimized geometry is manufactured and tested and is found to be 3.9% more efficient than the baseline with reduced cavitation at high flow. In the second approach, only the 3D inverse design method output is used to compute the efficiency and cavitation parameters and this leads to considerable reduction to the computational time. The resulting optimized geometry is found to be similar to the computationally more expensive solution based on 3D CFD results. In order to compare the inverse design based optimization to the conventional optimization, an equivalent optimization is carried out by parametrizing the blade angle and meridional shape.

scholarly journals Design and Performance Analysis of Contra-rotating Pumpjet Propulsor under Condition of Torque Unbalance

2018 ◽  
Vol 167 ◽  
pp. 03006
Author(s):  
Xiao-er Wang ◽  
Zhen-shan Zhang ◽  
Meng Zhang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Design Method ◽  
Three Dimensional ◽  
Underwater Vehicle ◽  
Inverse Design ◽  
Parameter Design ◽  
Power Difference ◽  
Inverse Design Method ◽  
And Performance

In order to balance the torque of front rotor and rear rotor of underwater vehicle, the analysis of the speed triangles at the inlet and outlet of the front and rear rotor has been done. Then, the thought of using contra-rotating pumpjet to achieve the objective was raised. The stator is installed behind the rear rotor so as to ensure the overall torque of the propulsor balance, at the same time, the stator can also support the shroud of the propulsor. the parameter design of the rotor and the stator has been carried out by using the three dimensional inverse design method. At last, the performance of the designed pumpjet propulsor is obtained when it is installed on the underwater vehicle By using computational fluid dynamics. The results show that the total torque of the propulsor is reduced to 1.8 N * m on the design point although the power difference ratio of the front rotor and the rear rotor is 20%. The torque ratio is also reduced from 4.6% to 0.4%, which is good to meet the propulsor balance requirement and verifies the 3-D design method of pumpjet is effective.

scholarly journals Functional assessment of cerebral artery stenosis: A pilot study based on computational fluid dynamics

2016 ◽  
Vol 37 (7) ◽  
pp. 2567-2576 ◽  
Author(s):  
Jia Liu ◽  
Zhengzheng Yan ◽  
Yuehua Pu ◽  
Wen-Shin Shiu ◽  
Jianhuang Wu ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Stokes Equations ◽  
Pressure Ratio ◽  
Invasive Procedure ◽  
Intracranial Stenosis ◽  
Parallel Computer ◽  
Invasive Technique ◽  
Non Invasive ◽  
Dynamics Method

The fractional pressure ratio is introduced to quantitatively assess the hemodynamic significance of severe intracranial stenosis. A computational fluid dynamics-based method is proposed to non-invasively compute the FPRCFD and compared against fractional pressure ratio measured by an invasive technique. Eleven patients with severe intracranial stenosis considered for endovascular intervention were recruited and an invasive procedure was performed to measure the distal and the aortic pressure ( Pd and Pa). The fractional pressure ratio was calculated as [Formula: see text]. The computed tomography angiography was used to reconstruct three-dimensional (3D) arteries for each patient. Cerebral hemodynamics was then computed for the arteries using a mathematical model governed by Navier–Stokes equations and with the outflow conditions imposed by a model of distal resistance and compliance. The non-invasive [Formula: see text], [Formula: see text], and FPRCFD were then obtained from the computational fluid dynamics calculation using a 16-core parallel computer. The invasive and non-invasive parameters were tested by statistical analysis. For this group of patients, the computational fluid dynamics method achieved comparable results with the invasive measurements. The fractional pressure ratio and FPRCFD are very close and highly correlated, but not linearly proportional, with the percentage of stenosis. The proposed computational fluid dynamics method can potentially be useful in assessing the functional alteration of cerebral stenosis.

Comparisons of Magnetic Resonance Imaging Velocimetry With Computational Fluid Dynamics

1997 ◽  
Vol 119 (1) ◽  
pp. 103-109 ◽  
Author(s):  
B. Newling ◽  
S. J. Gibbs ◽  
J. A. Derbyshire ◽  
D. Xing ◽  
L. D. Hall ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Magnetic Resonance ◽  
Flow Field ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Resonance Imaging ◽  
Pipe System

The flow of Newtonian liquids through a pipe system comprising of a series of abrupt expansions and contractions has been studied using several magnetic resonance imaging (MRI) techniques, and also by computational fluid dynamics. Agreement between those results validates the assumptions inherent to the computational calculation and gives confidence to extend the work to more complex geometries and more complex fluids, wherein the advantages of MRI (utility in opaque fluids and noninvasiveness) are unique. The fluid in the expansion-contraction system exhibits a broad distribution of velocities and, therefore, presents peculiar challenges to the measurement technique. The MRI protocols employed were a two-dimensional tagging technique, for rapid flow field visualisation, and three-dimensional echo-planar and gradient-echo techniques, for flow field quantification (velocimetry). The Computational work was performed using the FIDAP package to solve the Navier-Stokes equations. The particular choice of parameters for both MRI and computational fluid dynamics, which affect the results and their agreement, have been addressed.

scholarly journals Force and torque on spherical particles in micro-channel flows using computational fluid dynamics

2016 ◽  
Vol 3 (7) ◽  
pp. 160298 ◽  
Author(s):  
Jin Suo ◽  
Erin E. Edwards ◽  
Ananyaveena Anilkumar ◽  
Todd Sulchek ◽  
Don P. Giddens ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cell Adhesion ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Spherical Particles ◽  
Microfluidic Channels ◽  
Cfd Modelling ◽  
Cfd Simulations ◽  
Hemodynamic Force

To delineate the influence of hemodynamic force on cell adhesion processes, model in vitro fluidic assays that mimic physiological conditions are commonly employed. Herein, we offer a framework for solution of the three-dimensional Navier–Stokes equations using computational fluid dynamics (CFD) to estimate the forces resulting from fluid flow near a plane acting on a sphere that is either stationary or in free flow, and we compare these results to a widely used theoretical model that assumes Stokes flow with a constant shear rate. We find that while the full three-dimensional solutions using a parabolic velocity profile in CFD simulations yield similar translational velocities to those predicted by the theoretical method, the CFD approach results in approximately 50% larger rotational velocities over the wall shear stress range of 0.1–5.0 dynes cm −2 . This leads to an approximately 25% difference in force and torque calculations between the two methods. When compared with experimental measurements of translational and rotational velocities of microspheres or cells perfused in microfluidic channels, the CFD simulations yield significantly less error. We propose that CFD modelling can provide better estimations of hemodynamic force levels acting on perfused microspheres and cells in flow fields through microfluidic devices used for cell adhesion dynamics analysis.

Optimization of 6.2:1 Pressure Ratio Centrifugal Compressor Impeller by 3D Inverse Design

2011 ◽  
Author(s):  
M. Zangeneh ◽  
N. Amarel ◽  
K. Daneshkhah ◽  
H. Krain
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Mechanical Performance ◽  
Design Method ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Inverse Design ◽  
Transonic Compressor ◽  
Design Variables ◽  
Compressor Impeller

In this work, the redesign of a centrifugal transonic compressor impeller with splitter blades by means of the three-dimensional inverse design code TURBOdesign-1 is presented. The basic design methodology for impellers with splitter blades is outlined and is applied in a systematic way to improve the aero/mechanical performance of a transonic 6.2:1 pressure ratio centrifugal compressor impeller. The primary design variables are the main and splitter blades loading and their thickness distributions, the splitter to main blade work ratio, as well as the span-wise swirl distribution. The flow in the original and redesigned impellers are then analyzed by means of a commercial CFD code (ANSYS CFX). The predicted flow field for the original impeller is compared with detailed L2F measurements inside and outside the impeller. The validated CFD results are used to compare the flow field in the optimized and original impeller. It is shown that the inverse design method could be effectively used to control the position and strength of the shock waves, eliminate flow separation and hence obtain a more uniform impeller exit flow in order to improve the aerodynamic performance. In addition, some results are presented on the comparison of stress and vibration in both impellers.

Aerodynamic Design of a Highly Loaded Axial Flow Fan Rotor Using a Novel One-Dimensional Design Method With its Numerical Simulation

2016 ◽  
Author(s):  
Ali Shahsavari ◽  
Mahdi Nili-Ahamadabadi
Keyword(s):  
Numerical Simulation ◽  
Design Method ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Axial Flow ◽  
Numerical Results ◽  
Meridional Plane ◽  
Performance Curve ◽  
One Dimensional ◽  
Bypass Ratio

This paper presents a novel one-dimensional design method based on the radial equilibrium theory and constant span-wise diffusion factor to redesign of NASA rotor 67 just aerodynamically with a higher pressure ratio at the same design point. A one-dimensional design code is developed to obtain the meridional plane and blade to blade geometry of rotor to reach the three-dimensional view of rotor blades. To verify the redesigned rotor, its flow numerical simulation is carried out to compute its performance curve. The experimental performance curve of NASA rotor 67 is used for validation of the numerical results. Structured mesh with finer grids near walls is used to capture flow field and boundary layer effects. RANS equations are solved by finite volume method for rotating zones and stationary zones. The numerical results of the new rotor show about 9% increase in its pressure ratio at both design and off design mass flow rate. The new rotor has a higher outlet velocity through its upper span improving bypass ratio of a turbofan engine. To prove the new fan ability of producing more bypass ratio, a thermodynamic analysis is conducted. The results of this analysis show 13% increase in bypass ratio and 5.7% decline in specific fuel consumption in comparison to NASA rotor 67.

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