Investigation of Inlet Bent-Pipe’s Effect on a Turbocharger Compressor: Unsteadiness of Mass Glow and Location of Main Flow Loss

2014 ◽  
Author(s):  
Ben Zhao ◽  
Dazhong Lao ◽  
Liangjun Hu ◽  
Ce Yang
Keyword(s):  
Centrifugal Compressor ◽  
High Load ◽  
Bench Test ◽  
Inlet Pipe ◽  
Straight Pipe ◽  
Flow Distortion ◽  
Design Point ◽  
Bent Pipe ◽  
Flow Loss ◽  
Compressor Performance

As inlet bent-pipes are often used in vehicle turbocharger compressors, understanding of the inlet bent-pipe’s effect on centrifugal compressor and the mechanism of flow loss is important to improve the turbocharger compressor performance. Experiment and numerical simulation were carried out on a centrifugal compressor with straight pipe and bent-pipe. Numerical simulated compressor performance was compared with test data obtained from compressor flow bench test and to validate the numerical method. The analysis is mainly based on numerical results and it indicated that the inlet bent pipe induces a serious distortion at impeller inlet and increases the risk of blade high-cycle fatigue. The level of distortion changes to be more serious as the operation point of compressor varies from design point to high load. When an impeller channel enters distortion, the larger pressure difference between inlet and outlet makes this channel get clogged and the flow rate through this channel is reduced. At design point the bent pipe mainly influences the flow loss in the inlet pipe and impeller while at high load more serious flow distortion induced by bent-pipe is able to extend its stronger effect to the downstream diffuser and volute.

Effect of Different Geometrical Inlet Pipes on a High Speed Centrifugal Compressor

2013 ◽  
Author(s):  
Ce Yang ◽  
Ben Zhao ◽  
C. C. Ma ◽  
Dazhong Lao ◽  
Mi Zhou
Keyword(s):  
Centrifugal Compressor ◽  
High Speed ◽  
Pressure Ratio ◽  
Inlet Pipe ◽  
Unsteady Pressure ◽  
Bent Pipe ◽  
Low Mass ◽  
Compressor Performance ◽  
Spectral Frequency ◽  
The One

Two different inlet configurations, including a straight pipe and a bent pipe, were experimentally tested and numerically simulated using a high-speed, low-mass flow centrifugal compressor. The pressure ratios of the compressor with the two inlet configurations were tested and then compared to illustrate the effect of the bent inlet pipe on the compressor. Furthermore, different circumferential positions of the bent inlet pipe relative to the volute are discussed for two purposes. One purpose is to describe the changes in the compressor performance that result from altering the circumferential position of the bent inlet pipe relative to the volute. This change in performance may be the so-called clocking effect, and its mechanism is different from the one in multistage turbomachinery. The other purpose is to investigate the unsteady flow for different matching states of the bent inlet pipe and volute. Thus, the frequency spectrum of unsteady pressure fluctuation was applied to analyze the aerodynamic response. Compared with the straight inlet pipe, the experimental results show that the pressure ratio is modulated and that the choke point is shifted in the bent inlet pipe. Similarly, the pressure ratio can be influenced by altering the circumferential position of the bent inlet pipe relative to the volute, which may have an effect on the unsteady pressure in the rotor section. Therefore, the magnitude of interest spectral frequency is significantly changed by clocking the bent inlet pipe.

The Influence of Inlet Flow Distortion on the Performance of a Centrifugal Compressor and the Development of Improved Inlet Using Numerical Simulations—Part II: Development of Improved Inlet for a Centrifugal Compressor Using Numerical Simulations

2000 ◽  
Author(s):  
Yunbae Kim ◽  
Abraham Engeda ◽  
Ron Aungier ◽  
Greg Direnzi
Keyword(s):  
Numerical Simulations ◽  
Centrifugal Compressor ◽  
Curvature Radius ◽  
Flow Properties ◽  
Inlet Pipe ◽  
Flow Distortion ◽  
Cross Sectional ◽  
Inlet System ◽  
Compressor Inlet ◽  
Compressor Performance

Abstract Part I of this paper reported the experimental investigation on the effect of the curved inlet pipe flow distortion on a centrifugal compressor performance, which motivated the need of a new inlet design as well as a clear picture of the detailed flow field in the existing inlet design using numerical simulations. In Part II, new designs of different inlet systems as well as the design methods are discussed based on the comparison of flow properties at pipe exit of each design. The goal of the compressor inlet system design is to reduce the secondary flow and provide uniform flow for a compressor. Two design approaches are reported in this paper, one of which is the location of vanes and the other is the length of curvature radius, resulting in four new designs. The vanes are spaced in such a way that each passage shares the same pressure difference in radial direction. Numerical simulation results are presented in terms of mass averaged parameters and flow structures on the exit cross-sectional area. The design of original bend pipe with two vanes inside shows advantages over others.

Parametric Studies of Pipe Diffuser on Performance of a Highly Loaded Centrifugal Compressor

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Ge Han ◽  
Xingen Lu ◽  
Shengfeng Zhao ◽  
Chengwu Yang ◽  
Junqiang Zhu
Keyword(s):  
Centrifugal Compressor ◽  
Performance Enhancement ◽  
Detailed Comparison ◽  
Flow Distortion ◽  
Flow Solver ◽  
Beneficial Effects ◽  
Physical Mechanisms ◽  
Parametric Studies ◽  
Compressor Performance ◽  
Highly Loaded

Pipe diffusers with several different geometries were designed for a highly loaded centrifugal compressor originally using a wedge diffuser. Parametric studies on the effect of pipe diffuser performance of a highly loaded centrifugal compressor by varying pipe diffuser inlet-to-impeller exit radius ratio, throat length, divergence angle, and throat area on centrifugal compressor performance were performed using a state-of-the-art multiblock flow solver. An optimum design of pipe diffuser was obtained from the parametric study, and the numerical results indicate that this pipe diffuser has remarkable advantageous effects on the compressor performance. Furthermore, a detailed comparison of flow visualization between the pipe diffuser and the wedge diffuser was conducted to identify the physical mechanism that account for the beneficial effects of the pipe diffuser on the performance and stability of the compressor. It was found that the performance enhancement afforded by the pipe diffuser is a result of the unique diffuse inlet flow pattern. Alleviating flow distortion in the diffuser inlet and reducing the possibility of a flow separation in discrete passages are the physical mechanisms responsible for improving the highly loaded centrifugal compressor performance.

Synthetically Aerodynamic Design and Optimization on the Stationary Units of Centrifugal Compressor

2009 ◽  
Author(s):  
Rui Wang ◽  
Datong Qi ◽  
Yijun Mao
Keyword(s):  
Centrifugal Compressor ◽  
Coupling Effect ◽  
Flow Simulation ◽  
Air Separation ◽  
Experimental Result ◽  
Operating Efficiency ◽  
Flow Distortion ◽  
Recovery Coefficient ◽  
Design And Optimization ◽  
Flow Loss

The operating efficiency of a centrifugal compressor installed in air-separation plant was lower than the design parameter. In order to analyze the cause, a flow simulation on the whole centrifugal compressor was carried out on a parallel computational platform. The numerical results show that the inefficiency of the compressor was mainly caused by the flow loss in the stationary units. A synthetically aerodynamic redesign and optimization on the stationary units of the centrifugal compressor was performed to improve its polytrophic efficiency. Firstly, radial splitter vanes were appended in the flow passage of suction chamber to balance the flow loss and depress inlet flow distortion. Secondly, the meridian curve of the crossover and return channel was numerically optimized by using a combined neural network and genetic algorithm (GA) approach. Lastly, the b3/b2 of the vaneless diffuser was advanced to improve its total pressure recovery coefficient. An experimental measurement was carried out to validate the coupling effect of the improved stationary units to the centrifugal compressor performance. The experimental result shows that 4% advancement of the polytrophic coefficient of the centrifugal compressor has been achieved.

Numerical Analysis on Effects of Inlet Bent Pipe’s Position on a Centrifugal Compressor’s Aerodynamic Noise

2014 ◽  
Vol 633-634 ◽  
pp. 1196-1201
Author(s):  
Shu Guang Zuo ◽  
Hui Juan He ◽  
Xu Dong Wu ◽  
Kai Jun Wei
Keyword(s):  
Centrifugal Compressor ◽  
Power Level ◽  
Engineering Application ◽  
Aerodynamic Noise ◽  
Pipe Diameter ◽  
Aerodynamic Design ◽  
Straight Pipe ◽  
Bent Pipe ◽  
Rotational Direction ◽  
Pipe Outlet

The inlet connection of a centrifugal compressor is a bent pipe, and a straight pipe is installed between the bent pipe outlet and impeller inlet. The effect of different lengths of the straight pipe on the aerodynamic noise of a centrifugal compressor is numerically simulated. Theresult show that it’s essential to value the inlet bent pipe’s position in the inlet and outlet aerodynamic design. With the increase of straight pipe’s length, the noise radiated from the inlet decreases. When the length is over the pipe diameter, it has little effect on the outlet noise. The increase of straight pipe’s length also makes the circumferential noise decrease. The noise is distorted at approximately 90 ° in the rotational direction of the volute tongue. The sound power level of the compressor decreases to a constant value with the length over the pipe diameter. In the engineering application on aerodynamic noise, the straight pipe’s length before impeller inlet should be longer than the pipe diameter.

Numerical Investigation of the Flow Distortion Impact on a Refrigeration Centrifugal Compressor

2016 ◽  
Author(s):  
Feng Shen ◽  
Lei Yu ◽  
William T. Cousins ◽  
Vishnu Sishtla ◽  
Om P. Sharma
Keyword(s):  
Centrifugal Compressor ◽  
Computational Cost ◽  
Major Effect ◽  
Tip Clearance ◽  
Cfd Modeling ◽  
Inlet Pipe ◽  
Flow Distortion ◽  
Guide Vanes ◽  
Stall Margin ◽  
Steady Simulation

The inlet pipe to a centrifugal compressor in a water-cooled chiller can cause complexities in designing a compact unit. Flow distortion caused by the inlet pipe shape and non-uniformity of the flow from the evaporator can affect the compressor performance. Inlet guide vanes (IGVs) used for capacity control may help reduce the distortion by forcing a redistribution of the flow. However, the guide vanes themselves result in increased losses and can introduce flow distortion due to the clearance between the movable vane and stationary housing. In this effort, the influence of the flow distortion on the impeller performance and the losses caused by IGVs were investigated using a commercial code dealing with real gas. The CFD model was first verified by comparison to test data. Further investigation showed that the hub-to-shroud flow distortion, especially shroud side distortion, has a major effect on stage performance. IGVs are necessary for straightening the incoming flow to benefit stall margin but generate high losses themselves. The tip clearance of the IGV decreases the deswirl capability and introduces additional local separation loss. Distortion intensity was calculated according to ARP-1420 methods to justify the usage of the mixing plane in the CFD modeling. The extent of distortion indicated that the steady simulation served as a preferable choice for balancing computational cost & prediction accuracy.

Effects of Upstream Bend on Aerodynamic Performance of a Transonic Centrifugal Compressor

2019 ◽  
Author(s):  
Kazutoyo Yamada ◽  
Masato Furukawa ◽  
Hiromitsu Arai ◽  
Sasuga Ito
Keyword(s):  
Flow Rate ◽  
Centrifugal Compressor ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Circumferential Velocity ◽  
Low Flow ◽  
Inlet Pipe ◽  
Reversed Flow ◽  
Transonic Centrifugal Compressor ◽  
Bent Pipe

Abstract This paper describes the influence of a bent inlet pipe installed immediately upstream of a transonic centrifugal compressor on the aerodynamic performance and the stability. In order to clarify the influence of the bent inlet pipe, the internal flow fields in the inlet pipe, the impeller, and the diffuser of the compressor have been numerically investigated by a DES (Detached Eddy Simulation). For the purpose of comparison, the simulation was also conducted for the case of uniform axial inflow using a straight pipe. In order to make clear the influence of non-uniform flow with a bent pipe as far as possible, a 90-degree bent pipe was installed immediately upstream of the compressor, that is 0.86 times the inlet inner diameter. In the case of installing the bent pipe on the upstream of the compressor, the pressure ratio decreased on the high flow rate side in the compressor performance characteristic, whereas it increased at the low flow rate side. At the low flow rate operating point, there is a reversed flow occurring in the compressor impeller on the shroud side near the blade leading-edge. Installation of the bent pipe promotes mixing between the reversed flow and the main flow at the inlet of the compressor thanks to occurrence of a secondary flow. Since the reversed flow comes out from inside of the impeller, it has a high circumferential velocity. Therefore, the mixing of the reversed flow makes the compressor inlet flow a pre-swirl flow, and thereby the incidence decreases. As a result, leading-edge separation on the blade tip side of the impeller is suppressed, and the flow field inside the impeller is improved. In the diffuser section, when the bent pipe is installed, the circumferential velocity of the impeller exit flow increases on the hub side, whereas the radial velocity decreases. As a result, the diffuser performance is deteriorated and the diffuser stall tends to occur.

Effects of Diffuser Vane Geometries on Compressor Performance and Noise Characteristics in a Centrifugal Compressor

2013 ◽  
Author(s):  
Yohei Morita ◽  
Nobumichi Fujisawa ◽  
Takashi Goto ◽  
Yutaka Ohta
Keyword(s):  
Centrifugal Compressor ◽  
Noise Level ◽  
Leading Edge ◽  
Broadband Noise ◽  
Frequency Noise ◽  
Numerical Techniques ◽  
Vaned Diffuser ◽  
Noise Characteristics ◽  
Edge Vortex ◽  
Compressor Performance

The effects of the diffuser vane geometries on the compressor performance and noise characteristics of a centrifugal compressor equipped with vaned diffusers were investigated by experiments and numerical techniques. Because we were focusing attention on the geometries of the diffuser vane’s leading edge, diffuser vanes with various leading edge geometries were installed in a vaned diffuser. A tapered diffuser vane with the tapered portion near the leading edge of the diffuser’s hub-side could remarkably reduce both the discrete frequency noise level and broadband noise level. In particular, a hub-side tapered diffuser vane with a taper on only the hub-side could suppress the development of the leading edge vortex (LEV) near the shroud side of the diffuser vane and effectively enhanced the compressor performance.

Numerical Analysis of Deposits and Corrosion Influence on a Centrifugal Compressor Performance

2012 ◽  
Author(s):  
Mohammad R. Aligoodarz ◽  
Mohammad Reza Soleimani Tehrani ◽  
Hadi Karrabi ◽  
Mohammad R. Roshani
Keyword(s):  
Numerical Modeling ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Mechanical Damage ◽  
3D Numerical Modeling ◽  
Compressor Blades ◽  
Turbine Performance ◽  
Common Causes ◽  
Sst Turbulence Model ◽  
Compressor Performance

Turbo machineries including compressors performance degrades over the period of operation and deviates from design levels due to causes including dust entrance into the compressor, blades mechanical damage, erosion and corrosion. These lead to reduction in compressor performance, efficiency and pressure ratio. Subsequently gas turbine performance is affected since their operation sate is correlated. In this study the numerical investigation of common causes that determine geometric characteristics of a 2-stage centrifugal compressor running in a gas station, including blades fouling and corrosion is performed. 3D Numerical modeling is implemented along with utilization of Shear Stress Transport (SST) turbulence model and independency from the grids is verified.

Improving a one-dimensional centrifugal compressor performance prediction method

2005 ◽  
Vol 219 (8) ◽  
pp. 653-659 ◽  
Author(s):  
E Swain
Keyword(s):  
Centrifugal Compressor ◽  
Performance Prediction ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Prediction Method ◽  
Compressor Cascade ◽  
One Dimensional ◽  
Compressor Performance ◽  
Cfd Analyses

A one-dimensional centrifugal compressor performance prediction technique that has been available for some time is updated as a result of extracting the component performance from three-dimensional computational fluid dynamic (CFD) analyses. Confidence in the CFD results is provided by comparison of overall performance for one of the compressor examples. The extracted impeller characteristic is compared with the original impeller loss model, and this indicated that some improvement was desirable. The position of least impeller loss was determined using a traditional axial compressor cascade method, and suitable algebraic expressions were derived to match the CFD data. The merit of the approach lies with the relative ease that CFD component performance currently can be achieved and adjusting one-dimensional methods to agree with the CFD-derived models.

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