scholarly journals Sensitivity analysis of centrifugal compressors aerodynamic losses using 1D-mean streamline prediction technique

2021 ◽  
Vol 2128 (1) ◽  
pp. 012029
Author(s):  
Mostafa Mahmoud ◽  
S. Shaaban
Keyword(s):  
Sensitivity Analysis ◽  
Operating Conditions ◽  
Negligible Effect ◽  
Centrifugal Compressors ◽  
Aerodynamic Loss ◽  
Analysis Methodology ◽  
Disk Friction ◽  
Compressor Performance ◽  
Semi Empirical ◽  
Aerodynamic Losses

Abstract One-dimensional modeling and prediction of the centrifugal compressor performance are challenging as they require conservation equations and empirical and semi-empirical correlations. Therefore, there is a need to perform a consolidated study of the compressor aerodynamic loss models to conclude the importance of each loss to the compressor performance modeling. Accordingly, the purpose of this paper is to examine the effect of each aerodynamic loss on the compressor performance and explore more about which loss could have a negligible effect on the compressor performance. A MATLAB code was developed to predict the performance of five different small turbocharger centrifugal compressors at different geometric and operating conditions. The developed code was validated using the available experimental data of the investigated compressors. A sensitivity analysis methodology was performed using the validated code to check the effect of ten aerodynamic losses for the impeller and volute sections on the compressor performance. This paper concludes that impeller disk friction, blade loading, and clearance losses have a negligible effect on the small turbocharger vanless diffuser compressor performance.

Numerical Optimization and Manufacturing of the Impeller of a Centrifugal Compressor by Variation of Splitter Blades

2016 ◽  
Author(s):  
S. Abolfazl Moussavi Torshizi ◽  
Ali Hajilouy Benisi ◽  
Mohammad Durali
Keyword(s):  
Operating Conditions ◽  
Structural Defects ◽  
Cnc Machine ◽  
Centrifugal Compressors ◽  
Design And Optimization ◽  
Optimization Study ◽  
Wide Range ◽  
Destructive Analysis ◽  
Compressor Performance ◽  
Non Destructive

Design and optimization of centrifugal compressors, based on main blades configuration of impeller have been vastly discussed in open literature, but less researches have addressed splitters. In this research, the impeller of a commercial turbocharger compressor is investigated. Here, profiles of main blades are not changed while the effect of changing the configuration of splitters is studied. An optimization study is performed to find the best configuration using genetic algorithm over a complete operating curve of the compressor. CFD codes with experimental support are used to predict the compressor performance. Quantumetric tests beside destructive analysis of two impellers are implemented for material identification and selection which is necessary for manufacturing. After taking into account structural considerations and approving the safety by numerical simulation, the new impeller is manufactured using 5 axis CNC machine. Non destructive tests are performed for identification of any structural defects. The new impeller is then mounted on a turbocharger shaft and tested experimentally in a wide range of operating conditions, which leads to a design having 2.3% improvement in efficiency. This is an important achievement in all applications of centrifugal compressors, especially in turbochargers.

A Study Concerning Performance Characteristics of Centrifugal Compressors

1985 ◽  
Author(s):  
Shimpei Mizuki ◽  
Hikaru Imai
Keyword(s):  
Present Method ◽  
Relative Velocity ◽  
Operating Conditions ◽  
Performance Characteristics ◽  
Experimental Results ◽  
Flow Coefficient ◽  
Centrifugal Compressors ◽  
Specific Speed ◽  
Major Factors ◽  
Semi Empirical

A method for estimations of performance characteristics of centrifugal compressors was examined by comparing the estimated results with those by experiments. Lots of empirical and semi-empirical factors which were introduced to the losses within compressor channels in the estimations, and the experimental results for the compressors with a wide variety of configurations, operating conditions and design techniques were investigated. After the extensive comparisons, the most appropriate combinations of the factors for the present method were given. By employing this method, the major factors which are directly related to the performance characteristics were computed and the relationships among them were discussed. Thus, the ratio of the relative velocity at the impeller exit to that at the inlet, the non-dimensional relative velocity at the impeller inlet and that at the exit were obtained as the parameters of the slip factor, the flow coefficient and the specific speed.

Investigation and Prediction Models of the Axial Thrust in Centrifugal Compressors

2019 ◽  
Author(s):  
Mohand Younsi ◽  
Eric Hypolite
Keyword(s):  
Prediction Models ◽  
Numerical Approach ◽  
Empirical Models ◽  
Operating Conditions ◽  
Prediction Methods ◽  
Centrifugal Compressors ◽  
Axial Thrust ◽  
Rotating Impeller ◽  
Computational Fluid Dynamics Cfd ◽  
Semi Empirical

Abstract The purpose of this paper is to provide an overview of the prediction methods used to accurately determine the axial rotor thrust in centrifugal compressors. Thus, semi-empirical models were developed to estimate the aerodynamic forces acting on each side of the rotating impeller. In addition to this, a numerical approach based on Computational Fluid Dynamics (CFD) technique was carried out to simulate the 3D steady flow in the centrifugal compressor. The numerical simulations consider the entire geometry details. The resulting axial thrust, estimated by the semi-empirical approach and the CFD calculations, were compared to experimental data. The application of these approaches was extended and discussed at different operating conditions. Furthermore, the effect of the expeller vanes (pump-out-vanes) on the axial thrust was highlighted.

scholarly journals Sensitivity Analysis of OTEC-CC-MX-1 kWe Plant Prototype

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2585
Author(s):  
Jessica Guadalupe Tobal-Cupul ◽  
Estela Cerezo-Acevedo ◽  
Yair Yosias Arriola-Gil ◽  
Hector Fernando Gomez-Garcia ◽  
Victor Manuel Romero-Medina
Keyword(s):  
Sensitivity Analysis ◽  
Experimental Tests ◽  
Caribbean Sea ◽  
Ocean Model ◽  
Operating Conditions ◽  
Working Fluid ◽  
Ocean Energy ◽  
Mexican Caribbean ◽  
Water Temperature Data ◽  
Mass Flows

The Mexican Caribbean Sea has potential zones for Ocean Thermal Energy Conversion (OTEC) implementation. Universidad del Caribe and Instituto de Ciencias del Mar y Limnologia, with the support of the Mexican Centre of Innovation in Ocean Energy, designed and constructed a prototype OTEC plant (OTEC-CC-MX-1 kWe), which is the first initiative in Mexico for exploitation of this type of renewable energy. This paper presents a sensitivity analysis whose objective was to know, before carrying out the experimental tests, the behavior of OTEC-CC-MX-1 kWe regarding temperature differences, as well as the non-possible operating conditions, which allows us to assess possible modifications in the prototype installation. An algorithm was developed to obtain the inlet and outlet temperatures of the water and working fluid in the heat exchangers using the monthly surface and deep-water temperature data from the Hybrid Coordinate Ocean Model and Geographically Weighted Regression Temperature Model for the Mexican Caribbean Sea. With these temperatures, the following were analyzed: fluctuation of thermal efficiency, mass flows of R-152a and water and power production. By analyzing the results, we verified maximum and minimum mass flows of water and R-152a to produce 1 kWe during a typical year in the Mexican Caribbean Sea and the conditions when the production of electricity is not possible for OTEC-CC-MX-1 kWe.

Study on Characteristics of the Linear Air-Conditioner Compressor at Varied Operating Conditions

2011 ◽  
Vol 201-203 ◽  
pp. 632-636 ◽  
Author(s):  
Jie Fei Xie ◽  
Xin Hua Li ◽  
Hong Zhang
Keyword(s):  
Engineering Application ◽  
Axial Direction ◽  
Operating Conditions ◽  
Air Conditioner ◽  
Design Development ◽  
Runge Kutta Method ◽  
Moving Body ◽  
Cylinder Piston ◽  
Compressor Performance ◽  
Intake Pressure

This paper mainly introduces a novel linear air conditioner compressor which is driven by the linear oscillatory motor with two divided moving body, of which the Cylinder-piston assembly presents symmetrical distribution along the axial direction. The compressor dynamics equations were built and solved numerically with the fourth order Runge-Kutta method. in the meantime, this paper emphatically analyzes the influence of those factors, such as the intake pressure, the exhaust pressure, the suction gas superheat, the cooling degree, on the compressor performance at varied operating conditions. These works shows that improving the suction gas pressure and reducing the exhuast pressure can help to increase the refrigeration capacity and energy efficiency ratio of the air conditioner compressor. Those analysis results provide theory foundation for design,development, and engineering application of this linear air-conditioner compressor.

scholarly journals Aerodynamic Analysis of Multistage Turbomachinery Flows in Support of Aerodynamic Design

1999 ◽  
Author(s):  
John J. Adamczyk
Keyword(s):  
Unsteady Flow ◽  
Axial Flow ◽  
Operating Conditions ◽  
Design Environment ◽  
Cfd Simulations ◽  
Average Flow ◽  
Flow Models ◽  
Time Average ◽  
Semi Empirical ◽  
Future Work

This paper summarizes the state of 3D CFD based models of the time average flow field within axial flow multistage turbomachines. Emphasis is placed on models which are compatible with the industrial design environment and those models which offer the potential of providing credible results at both design and off-design operating conditions. The need to develop models which are free of aerodynamic input from semi-empirical design systems is stressed. The accuracy of such models is shown to be dependent upon their ability to account for the unsteady flow environment in multistage turbomachinery. The relevant flow physics associated with some of the unsteady flow processes present in axial flow multistage machinery are presented along with procedures which can be used to account for them in 3D CFD simulations. Sample results are presented for both axial flow compressors and axial flow turbines which help to illustrate the enhanced predictive capabilities afforded by including these procedures in 3D CFD simulations. Finally, suggestions are given for future work on the development of time average flow models.

scholarly journals The Design of an Improved Endwall Film-Cooling Configuration

1998 ◽  
Author(s):  
S. Friedrichs ◽  
H. P. Hodson ◽  
W. N. Dawes
Keyword(s):  
Secondary Flow ◽  
Film Cooling ◽  
Large Scale ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Aerodynamic Loss ◽  
Cooling Flow ◽  
High Static Pressure ◽  
Endwall Film Cooling ◽  
Aerodynamic Losses

The endwall film-cooling cooling configuration investigated by Friedrichs et al. (1996, 1997) had in principle sufficient cooling flow for the endwall, but in practice, the redistribution of this coolant by secondary flows left large endwall areas uncooled. This paper describes the attempt to improve upon this datum cooling configuration by redistributing the available coolant to provide a better coolant coverage on the endwall surface, whilst keeping the associated aerodynamic losses small. The design of the new, improved cooling configuration was based on the understanding of endwall film-cooling described by Friedrichs et al. (1996, 1997). Computational fluid dynamics were used to predict the basic flow and pressure field without coolant ejection. Using this as a basis, the above described understanding was used to place cooling holes so that they would provide the necessary cooling coverage at minimal aerodynamic penalty. The simple analytical modelling developed in Friedrichs et al. (1997) was then used to check that the coolant consumption and the increase in aerodynamic loss lay within the limits of the design goal. The improved cooling configuration was tested experimentally in a large scale, low speed linear cascade. An analysis of the results shows that the redesign of the cooling configuration has been successful in achieving an improved coolant coverage with lower aerodynamic losses, whilst using the same amount of coolant as in the datum cooling configuration. The improved cooling configuration has reconfirmed conclusions from Friedrichs et al. (1996, 1997); firstly, coolant ejection downstream of the three-dimensional separation lines on the endwall does not change the secondary flow structures; secondly, placement of holes in regions of high static pressure helps reduce the aerodynamic penalties of platform coolant ejection; finally, taking account of secondary flow can improve the design of endwall film-cooling configurations.

Powder Spheroidization Using Induction Plasma Technology

2000 ◽  
Author(s):  
N.M. Dignard ◽  
M.I. Boulos
Keyword(s):  
Energy Efficiency ◽  
Maximum Energy ◽  
Operating Conditions ◽  
Side Reactions ◽  
Induction Plasma ◽  
Silica Alumina ◽  
Change In The Mean ◽  
The Individual ◽  
Semi Empirical ◽  
Objective Being

Abstract An experimental study of the spheroidization efficiency of induction plasma processes was completed. The main objective being to obtain models which could be subsequently used for the prediction of the spheroidization efficiency for various powders and plasma operating conditions. Silica, alumina, chromium oxide and zirconia powders were treated during the experimentation. For the plasma treatment of the powders the installation used had a maximum available power of 50 kW with an operating frequency of 3 MHz. Operating conditions were varied such to minimize side reactions and the evaporation of powders. The resulting powders did show the presence of cavities and a slight change in the mean diameters. The maximum energy efficiency based semi-empirical model did predict the spheroidization efficiency of the particles beyond a defined critical point known as the maximum energy efficiency point. For the model, the maximum energy efficiency is distinct for the individual powders but remain within a defined range which is reflected in the small variations in the Z constant.

Interaction Between Two Closely Spaced Azimuthing Thrusters

1998 ◽  
Vol 42 (01) ◽  
pp. 15-32 ◽  
Author(s):  
Paul Brandner ◽  
Martin Renilson
Keyword(s):  
Mathematical Model ◽  
Satisfactory Agreement ◽  
Vehicle Dynamics ◽  
Operating Conditions ◽  
Towing Tank ◽  
Empirical Relations ◽  
Series Of Experiments ◽  
Flow Effects ◽  
Semi Empirical

To assist in predicting the performance of omni-directional propelled vehicles a series of experiments has been conducted to measure the interaction between two closely spaced ductedazimuthing thrusters. The thrusters were tested below a shallow draft ground board in a towing tank at a spacing of approximately 2 propeller diameters. Measurements were made of forces acting on a single thruster for a range of operating conditions and similarly on two thrusters for a range of relative positions. The results show that forces from the trailing thruster are heavily affected by interaction, particularly due to impingement of the race from the leading thruster, where as forces from the leading thruster remain essentially unaffected despite its proximity to the trailing thruster. A semi-empirical mathematical model suitable for simulation of omni-directional vehicle dynamics is presented. The model is based on the trajectory of the race from the leading thruster derived from momentum considerations with additional empirical relations to account for other more minor flow effects. Comparison of the predicted and measured results show satisfactory agreement.

Efficiency and Sensitivity Analysis of Cavern-Based CAES Systems During off-Design Operating Conditions

2021 ◽  
pp. 177-199
Author(s):  
Mehdi Ebrahimi ◽  
David S.-K. Ting ◽  
Rupp Carriveau ◽  
Andrew McGillis ◽  
David Brown
Keyword(s):  
Sensitivity Analysis ◽  
Operating Conditions
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