Experimental and numerical investigation of expansion corner effects on isolator performance

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Jaimon D. Quadros ◽  
Sher Afghan Khan ◽  
T. Prashanth
Keyword(s):  
Nozzle Exit ◽  
Static Pressure ◽  
Pressure Rise ◽  
Experimental Investigations ◽  
Shock Train ◽  
Flow Process ◽  
Cross Sectional ◽  
Static Pressure Distribution ◽  
Pitot Pressure ◽  
High Static Pressure

AbstractIn the present study, the effect of expansion corner on suddenly expanded flow process has been studied. Experimental investigations have been carried out on a convergent-divergent (C-D) nozzle and isolator duct, where the expansion of the channel is formed through the presence of a 1, 2 and 3 expansion corners (EC) respectively. Flow from nozzle exit of the nozzle of Mach, M = 2.0 was suddenly expanded into the axi-symmetric duct having a cross sectional area of 4.84 times the nozzle exit area. The wall static pressure along the length of the duct and the Pitot pressure at the exit plane of the duct were measured for all the configurations. Computational fluid dynamics (CFD) technique was employed for visualizing the shock-train in the expanded duct. The isolator with one expansion corner was found to be more efficient in achieving a high static pressure rise. The experimental and numerical wall static pressure distribution values were compared for isolators with EC = 2 and found to be in good agreement with each other with a maximum absolute percentage deviation of 11%.

Experimental Investigation of Shape Transition Effects on Isolator Performance

2018 ◽  
Vol 35 (4) ◽  
pp. 331-338
Author(s):  
G. Chandra Bose ◽  
S. Thanigaiarasu ◽  
S. Elangovan ◽  
E. Rathakrishnan
Keyword(s):  
Static Pressure ◽  
Pressure Rise ◽  
Experimental Investigations ◽  
Settling Chamber ◽  
Shape Transition ◽  
Shock Train ◽  
Cross Sectional ◽  
Pitot Pressure ◽  
Expansion Level ◽  
Transition Effects

Abstract Isolator is a critical component in supersonic air breathing engine and it is usually situated between the inlet and the combustor of a dual-mode ramjet/scramjet engine. In the present study, shape transition effects on isolator performance have been studied by carrying out experimental investigations on square, square to circular and square to elliptical transition ducts. The length of the isolator chosen in this study is 180 mm and the cross-sectional area of 900 mm2 is maintained constant along the length for all the ducts. Experiments were carried out for isolator inlet Mach 2, using a contoured nozzle. Varying the pressure of the settling chamber varied the expansion level at the nozzle exit, which run the nozzle. The wall static pressure along the length of the isolator and the Pitot pressure at the exit plane of the isolator were measured for all the configurations. Shadowgraph technique was employed for visualizing the shock-train in the isolator. The square to circular transition isolator is found to be more efficient in achieving the static pressure rise across the isolator than the square and square to elliptical transition ducts.

Experimental investigation of the effect of nozzle shape and test section perforation on the stationary and non-stationary characteristics of flow field in the large transonic TsAGI T-128 Wind tunnel

2005 ◽  
Vol 109 (1092) ◽  
pp. 75-82 ◽  
Author(s):  
V. I. Biryukov ◽  
S. A. Glazkov ◽  
A. R. Gorbushin ◽  
A. I. Ivanov ◽  
A. V. Semenov
Keyword(s):  
Wind Tunnel ◽  
Flow Field ◽  
Test Section ◽  
Static Pressure ◽  
Pressure Fluctuations ◽  
Flow Characteristics ◽  
Experimental Investigations ◽  
Drive Power ◽  
Static Pressure Distribution ◽  
Nozzle Shape

Abstract The results are presented for a cycle of experimental investigations of flow field characteristics (static pressure distribution, static pressure fluctuations, upwash, boundary-layer parameters) in the perforated test section of the transonic TsAGI T-128 Wind Tunnel. The investigations concern the effect of nozzle shape, wall open-area ratio, Mach and Reynolds numbers on the above-outlined flow characteristics. During the tests, the main Wind-tunnel drive power is measured. Optimal parameters of the nozzle shape and test section perforation are obtained to minimise acoustic perturbations in the test section and their non-uniformity in frequency, static pressure field non-uniformity, nozzle and test section drag and, accordingly, required main Wind-tunnel drive power.

scholarly journals Experimental Investigations of a Recently Developed Supersonic Compressor Stage (Rotor and Stage Performance)

1974 ◽  
Author(s):  
H. Simon ◽  
D. Bohn
Keyword(s):  
Static Pressure ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Strong Shock ◽  
Wall Pressure ◽  
Experimental Investigations ◽  
Pressure Measurements ◽  
Compressor Stage ◽  
Pressure Transducers ◽  
Rotor Type

The experimental investigations of a recently developed supersonic compressor stage working with a strong shock wave both in the rotor and stator are described. The shock in the inlet area of the rotor is stabilized by the geometry of the rotor blade channel, whereas the position of shocks in the stator is controlled by the back pressure. Due to this, the static pressure rise is distributed to the rotor and stator avoiding a higher loading of the stator. In the first part the performance of the rotor alone has been investigated. The conducted probe and static wall pressure measurements allowed a detailed analysis of the flow through the rotor. The determined performance characteristics of the rotor show the peculiarities of the rotor at different speeds and throttle positions. In addition to the static wall pressure measurements the nonsteady pressure distributions have been measured at the casing wall by piezoelectric pressure transducers. Since this rotor (type ②) has been designed with the same relative inlet Mach number and turning as the previously investigated supersonic rotor (type ①), a direct comparison of these rotors can be made. In the second part of these investigations the rotor of type ② has been combined with a tandem cascade as a stator, to investigate the supersonic compressor stage. With heavy throttling a static pressure ratio of 3,5 (p3/p1) has been achieved. The evaluation of the probe measurements allowed a better estimation of the overall performance of this supersonic compressor stage.

Measurement and Analysis of Static Pressure Field in a Torque Converter Pump

1995 ◽  
Vol 117 (1) ◽  
pp. 109-115 ◽  
Author(s):  
R. R. By ◽  
B. Lakshminarayana
Keyword(s):  
Pressure Distribution ◽  
Potential Flow ◽  
Static Pressure ◽  
Pressure Field ◽  
Pressure Rise ◽  
Torque Converter ◽  
Speed Ratio ◽  
Pump Speed ◽  
The Core ◽  
Static Pressure Distribution

In this paper, the static pressure field and performance parameters of a torque converter pump are measured, analyzed, and interpreted under three turbine/pump speed ratio conditions (0, 0.6, and 0.8). A potential flow code is used to predict the static pressure distribution. Results show that: 1) centrifugal force has a dominant effect on the static pressure rise in the pump; 2) the static pressure field is generally poor at the core section; and 3) the potential flow code can fairly well predict the static pressure distribution at the blade mid-span, but not at the core and shell sections.

scholarly journals Casing wall static pressure distribution behavior in a centrifugal compressor with asymmetric inlet/outlet structures

2018 ◽  
Vol 233 (1) ◽  
pp. 37-51 ◽  
Author(s):  
Ce Yang ◽  
Hanzhi Zhang ◽  
Dengfeng Yang ◽  
Dazhong Lao ◽  
Changmao Yang
Keyword(s):  
Pressure Distribution ◽  
Flow Rate ◽  
Static Pressure ◽  
Inlet Pipe ◽  
Static Pressure Distribution ◽  
Bent Pipe ◽  
Small Flow ◽  
High Static Pressure ◽  
Casing Pressure ◽  
Distribution Behavior

Asymmetric structures of the bent inlet pipes and outlet volute are typically adopted in centrifugal compressors. By using asymmetric inlet/outlet structures, the uniformity of the compressor’s internal flow field in the circumferential direction will be changed. The static pressure distribution behavior around the casing wall is significantly influenced by the coupling effect of the bent inlet pipe and outlet volute. In the present work, three compressors were numerically and experimentally investigated. One compressor had a straight inlet pipe, and the other two had bent inlet pipes. Seventy-two static pressure sensors were mounted around the casing wall to obtain the static pressure distribution at different flow rates for three rotational speeds. The results show that at high rotational speeds with large flow rate conditions, when the static pressure waves induced by the bent pipe and volute act on the same circumferential position, the casing wall static pressure will be increased at the corresponding position. Furthermore, this high static pressure will further influence the static pressure values at other circumferential positions and leads to a more nonuniform circumferential static pressure distribution. Near the design flow rate, when the high static pressure strips, which are induced by both the bent pipe and volute impact different circumferential positions, the high static pressure strip induced by the volute will be weakened. As a result, the high static pressure strip induced by the volute cannot propagate upstream into the impeller. At small flow rate under designed rotational speed, the influence of the volute tongue on the casing pressure distribution will be enhanced. At small flow rate under low rotational speed, the casing pressure distributions of the three models were almost the same because the secondary flow effect of the bent pipe diminishes as the flow rate reduces.

scholarly journals Experimental Investigations of Supersonic Cascades Designed for High Static Pressure Ratios

1977 ◽  
Author(s):  
R. Fuchs ◽  
H. Starken
Keyword(s):  
Total Pressure ◽  
Static Pressure ◽  
Research Work ◽  
Axial Direction ◽  
Experimental Investigations ◽  
Blade Row ◽  
Stator Blade ◽  
High Static Pressure ◽  
Inlet Conditions ◽  
Very High

The outlet conditions of supersonic compressor rotors designed for very high total pressure ratios can be highly supersonic (impulse rotors). Then the following stator blade row has to build up high static pressure ratios at supersonic inlet conditions. This paper describes part of a research work which should answer, if it is at all possible to realize such high static pressure ratios in a cascade. Cascades with convergent-divergent blade passages were designed and optimized by boundary layer calculations. In a first step no flow turning was incorporated in the blade sections. A three-shock-type cascade was found to be an optimum design The wind tunnel measurements resulted in static pressure ratios of the order of 6 and total pressure ratios of 0.77 at inlet Mach numbers of 2.2. In a second step the flow turning to axial direction was realized. For that two types of cascades were built and tested. One was a tandem type cascade and the other a single row cascade. The experiments at inlet design conditions resulted in static pressure ratios of the order of 6.5 and total pressure ratios of 0.72.

Performance and wall static pressure measurements on centrifugal compressor diffusers

2003 ◽  
Vol 217 (5) ◽  
pp. 547-558 ◽  
Author(s):  
J. M. Issac ◽  
N Sitaram ◽  
M Govardhan
Keyword(s):  
Centrifugal Compressor ◽  
Static Pressure ◽  
Experimental Studies ◽  
Pressure Rise ◽  
Leading Edge ◽  
Large Area ◽  
Static Pressure Distribution ◽  
Flow Adjustment ◽  
Separation Zones ◽  
Vane Diffuser

The results of experimental studies on performance and wall static pressure distribution in the diffuser passage of a low specific speed centrifugal compressor are given. The performance tests were carried out with vaneless, vane and low-solidity vane diffusers at speeds of 2500, 3000 and 3500r/min. Diffuser wall static pressures measured at 3000r/min for four flow coefficients on the shroud and hub walls are reported. The peak energy coefficient is maximum for the vane diffuser. The operating range of the low-solidity vane diffuser is wider than that of the vane diffuser. At high flow coefficients, the static pressure rise is substantially lower for the vane diffuser, as the incidence on the vane leading edge is very high. The low-solidity vane diffuser did not suffer a large drop in static pressure near the leading edge. The most probable reason may be the large area available in the low-solidity vane diffuser for flow adjustment and weaker flow separation zones on account of the lower number of vanes.

Mixing and Entrainment Characteristics in Circular Short Ejectors

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Ju Hyun Im ◽  
Seung Jin Song
Keyword(s):  
Shear Layer ◽  
Flow Velocity ◽  
Static Pressure ◽  
Control Volume ◽  
Flow Characteristics ◽  
Velocity Profiles ◽  
Secondary Flows ◽  
Experimental Investigations ◽  
Static Pressure Distribution ◽  
And Performance

Analytical and experimental investigations have been conducted to characterize the performance of “short” ejectors. In short ejectors, the core of primary (motive) flow still exists at the mixing duct exit, and nonuniform mixed flow is discharged from the mixing duct. Due to incomplete mixing, short ejector pumping performance is degraded and cannot be predicted by the existing “long” ejector models. The new analytical short ejector model presented in this paper is based on the control volume analysis and jet expansion model. The secondary (entrained) flow velocity and the corresponding shear layer (between the primary and the secondary flows) growth rate variations along the mixing duct are taken into account. In addition, measurements have been made in ejectors with length ratios (LRs) of two and three for an area ratio (AR) of 1.95; and a LR of two for an AR of 3.08. Velocity profiles at the mixing duct inlet and exit, and static pressure distribution along the mixing duct have been measured with pitot probes and pressure taps. All of the tests have been carried out at a Reynolds number of 420,000. Comparison shows that the new ejector model can accurately predict flow characteristics and performance of short ejectors. For all of the test cases, the velocity profiles at the mixing duct inlet and exit are well predicted. Also, both predictions and measurements show pumping enhancement with increasing mixing duct length. The pumping enhancement is due to the increase in the static pressure difference between the mixing duct inlet and atmosphere as the mixing duct is lengthened. Furthermore, both measured and predicted static pressure distributions along the mixing duct show a kink. According to the analysis, the kink occurs when the outer shear layer reaches the mixing duct wall, and the secondary flow velocity decreases along the mixing duct upstream of the kink and increases downstream of the kink. Thus, the new ejector model can accurately predict not only the integral performance but also different mixing regimes in short ejectors.

Numerical investigations on the effect of volute casing treatment for performance augmentation in a centrifugal fan

2021 ◽  
pp. 095440622110341
Author(s):  
Manjunath L Nilugal ◽  
K Vasudeva Karanth ◽  
Madhwesh N
Keyword(s):  
Total Pressure ◽  
Static Pressure ◽  
Numerical Study ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Centrifugal Fan ◽  
Casing Treatment ◽  
Sliding Mesh ◽  
Optimum Configuration

This article presents the effect of volute chamfering on the performance of a forward swept centrifugal fan. The numerical analysis is performed to obtain the performance parameters such as static pressure rise coefficient and total pressure coefficient for various flow coefficients. The chamfer ratio for the volute is optimized parametrically by providing a chamfer on either side of the volute. The influence of the chamfer ratio on the three dimensional flow domain was investigated numerically. The simulation is carried out using Re-Normalisation Group (RNG) k-[Formula: see text] turbulence model. The transient simulation of the fan system is done using standard sliding mesh method available in Fluent. It is found from the analysis that, configuration with chamfer ratio of 4.4 is found be the optimum configuration in terms of better performance characteristics. On an average, this optimum configuration provides improvement of about 6.3% in static pressure rise coefficient when compared to the base model. This optimized chamfer configuration also gives a higher total pressure coefficient of about 3% validating the augmentation in static pressure rise coefficient with respect to the base model. Hence, this numerical study establishes the effectiveness of optimally providing volute chamfer on the overall performance improvement of forward bladed centrifugal fan.

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