scholarly journals The M.I.T. Blowdown Compressor Facility

1974 ◽  
Vol 96 (4) ◽  
pp. 394-405 ◽  
Author(s):  
J. L. Kerrebrock ◽  
A. H. Epstein ◽  
D. M. Haines ◽  
W. T. Thompkins
Keyword(s):  
Steady State ◽  
Low Cost ◽  
Pressure Ratio ◽  
Decay Rates ◽  
Test Facility ◽  
Time Resolved ◽  
Transonic Compressor ◽  
Nominal Pressure ◽  
Design Speed ◽  
Steady State Performance

A Blowdown Compressor Test Facility has been developed which allows time resolved aerodynamic testing of full-scale transonic compressor rotors at low cost. The rotor is brought to speed in vacuum, a diaphragm is opened, and the test gas allowed to flow for a time of the order of one tenth sec, during which the rotor is driven by its own inertia. Both “steady-state” performance evaluation and detailed time resolution of the flow on the blade-passing time scale have been demonstrated for a two-ft dia transonic rotor with tangential Mach number of 1.2 and nominal pressure ratio of 1.6. The steady-state performance as determined in the experiments includes an efficiency of 0.92 and a pressure ratio of 1.55 at design speed. The time resolved measurements include the combination tone structure in the upstream flow field, resolved both axially and radially, and the wake structure downstream of the rotor, also resolved both radially and axially. The radial and axial variations of the rms amplitude of a dominant combination tone are found to agree well with duct mode theory, the axial dependence indicating a standing wave. From the wake measurements, preliminary estimates are given of wake spreading and decay rates, in rotor-exit flow fields.

Time Resolved Simulation and Experimental Validation of the Flow in Axial Slot Casing Treatments for Transonic Axial Compressors

2008 ◽  
Author(s):  
Giovanni A. Brignole ◽  
Florian C. T. Danner ◽  
Hans-Peter Kau
Keyword(s):  
Mass Flow ◽  
Total Pressure ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Compressor Stage ◽  
Time Resolved ◽  
Transonic Compressor ◽  
Design Speed ◽  
Casing Treatments ◽  
Total Pressure Ratio

Building on the experience of previous investigations, a casing treatment was developed and applied to an axial transonic compressor stage, in literature referred to as Darmstadt Rotor 1. The aerodynamics of the experimental compressor stage was improved by applying axially orientated semicircular slots to the original plain casing, which both enhanced the operating range and design point efficiency. A gain in total pressure ratio along the entire design speed line was also observed. Within the scope of this study four different axial casing treatments were designed. Their effect on the flow in a transonic axial compressor stage was investigated parametrically using time-resolved 3D-FANS simulations with a mesh of approximately 4.8 · 106 grid points. This research aims to identify correlations between the geometrical cavity design and the changed channel flow. The findings help to formulate parameters for evaluating the performance of casing treatments. These criteria can further be used as target functions in the design optimisation process. The predicted behaviour of the transonic compressor was validated against experiments as well as an alternative numerical model, the non-linear harmonic method. Both confirmed the effect of the slots in raising efficiency as well as moving the design speed line towards higher pressure ratios. In the experiments, the addition of the slots increased the total pressure ratio at stall conditions by more than 5% and reduced mass flow from 87.5% of the design mass flow to less than 77.5% compared to the original geometry.

Comparison of Time-Resolved Turbine Rotor Blade Heat Transfer Measurements and Numerical Calculations

1991 ◽  
Author(s):  
R. S. Abhari ◽  
G. R. Guenette ◽  
A. H. Epstein ◽  
M. B. Giles
Keyword(s):  
Heat Transfer ◽  
Rotor Blade ◽  
Pressure Ratio ◽  
Time History ◽  
Turbine Rotor ◽  
Numerical Calculations ◽  
Test Facility ◽  
Time Resolved ◽  
Turbine Rotor Blade ◽  
History Of

Time-resolved turbine rotor blade heat transfer data are compared with ab initio numerical calculations. The data was taken on a transonic, 4-to-1 pressure ratio, uncooled, single-stage turbine in a short duration turbine test facility. The data consists of the time history of the heat transfer distribution about the rotor chord at midspan. The numerical calculation is a time accurate, 2-D, thin shear layer, multiblade row code known as UNSFLO. UNSFLO uses Ni’s Lax-Wendroff algorithm, conservative boundary conditions, and a time tilting algorithm to facilitate the calculation of the flow in multiple blade rows of arbitrary pitch ratio with relatively little computer time. The version used for this work had a simple algebraic Baldwin-Lomax turbulence model. The code is shown to do a good job of predicting the quantitative time history of the heat flux distribution. The wake/boundary layer and transonic interaction regions for suction and pressure surfaces are identified and the shortcomings of the current algebraic turbulence modelling in the code are discussed. The influence of hardware manufacturing tolerance on rotor heat transfer variation is discussed. A physical reasoning explaining the discrepancies between the unsteady measurement and the calculations for both the suction and pressure surfaces are given, which may be of use in improving future calculations and design procedures.

Numerical Analysis to Investigate the Effect of Swept Rotor on the Overall Performance of a Transonic Compressor Stage

2014 ◽  
Author(s):  
Shobhavathy M. Thimmaiah ◽  
Ramesha Gurikelu ◽  
Nisha Sherief
Keyword(s):  
Flow Field ◽  
Total Pressure ◽  
Pressure Ratio ◽  
Stability Margin ◽  
Compressor Stage ◽  
Operating Range ◽  
Transonic Compressor ◽  
Overall Performance ◽  
Design Speed ◽  
The Stability

This paper presents the steady state numerical analyses carried out to investigate the effect of forward and backward swept rotor on the overall performance and stability margin of single stage transonic axial flow compressor. Initially, the analyses were carried out on a radially stacked rotor/baseline configuration and obtained the overall performance map of the compressor stage. These results were compared with the available experimental data for validation. Further, investigations were carried out on geometrically modified rotor with six configurations having 5, 10 and 15° forward and backward sweep. A commercial 3-Dimensional CFD package, ANSYS FLUENT was used to compute the complex flow field of transonic compressor rotors. The flow field structures were studied with the help of Mach number total pressure contours. The results of modified rotor geometry indicated that the peak adiabatic efficiency and the total pressure ratio for all the tested forward and backward swept rotor configurations are marginally higher than that of the baseline configuration at all speeds. The operating ranges of all the swept rotor configurations are found to be higher than that of the baseline configuration. The operating range is broader at lower operating speeds than at design speed condition. Rotor with 10° forward sweep and 5° backward sweep indicated the noteworthy improvement in the operating range against the baseline configuration. The stability margin of 11.3, 6.6, 5.2 and 3.5% at 60, 80, 90 and 100% of the design speed respectively compared to the baseline configuration obtained from 10° forward sweep. Rotor with 5° backward sweep showed the stability margin of 12, 4, 3.9 and 3% at 60, 80, 90 and 100% of the design speed respectively compared to the baseline configuration.

Comparison of Time-Resolved Turbine Rotor Blade Heat Transfer Measurements and Numerical Calculations

1992 ◽  
Vol 114 (4) ◽  
pp. 818-827 ◽  
Author(s):  
R. S. Abhari ◽  
G. R. Guenette ◽  
A. H. Epstein ◽  
M. B. Giles
Keyword(s):  
Heat Transfer ◽  
Rotor Blade ◽  
Pressure Ratio ◽  
Time History ◽  
Turbine Rotor ◽  
Numerical Calculations ◽  
Test Facility ◽  
Time Resolved ◽  
Turbine Rotor Blade ◽  
History Of

Time-resolved turbine rotor blade heat transfer data are compared with ab initio numerical calculations. The data were taken on a transonic, 4-to-1 pressure ratio, uncooled, single-stage turbine in a short-duration turbine test facility. The data consist of the time history of the heat transfer distribution about the rotor chord at midspan. The numerical calculation is a time accurate, two-dimensional, thin shear layer, multiblade row code known as UNSFLO. UNSFLO uses Ni’s Lax-Wendroff algorithm, conservative boundary conditions, and a time tilting algorithm to facilitate the calculation of the flow in multiple blade rows of arbitrary pitch ratio with relatively little computer time. The version used for this work had a simple algebraic Baldwin-Lomax turbulence model. The code is shown to do a good job of predicting the quantitative time history of the heat flux distribution. The wake/boundary layer and transonic interaction regions for suction and pressure surfaces are identified and the shortcomings of the current algebraic turbulence modeling in the code are discussed. The influence of hardware manufacturing tolerance on rotor heat transfer variation is discussed. A physical reasoning explaining the discrepancies between the unsteady measurement and the calculations for both the suction and pressure surfaces are given, which may be of use in improving future calculations and design procedures.

A convenient synthetic approach to obtain meso-Uracil-BODIPY

Synlett ◽  
2021 ◽  
Author(s):  
Mariachiara Trapani ◽  
Hans Elemans ◽  
Maria Angela Castriciano ◽  
Angelo Nicosia ◽  
Placido Giuseppe Mineo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Steady State ◽  
Low Cost ◽  
Photophysical Properties ◽  
Aldehyde Group ◽  
Synthetic Approach ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Uracil Derivatives ◽  
Convenient Synthetic Approach

An effective and convenient protocol for the synthesis of 1-Substituted-6-formyl-uracil derivatives has been developed. A three-step sequence has allowed obtaining new 6-Formyl uracil with various substituents at N-1, in large quantity using low-cost precursors. Uracil molecules containing an aldehyde group have been used as useful precursors for the preparation of meso-(1’-Substituted-6’-uracil)-BODIPY derivatives. In this way, regioselectively functionalized BODIPYs directly connected to a nucleobase were prepared in yields from 30 to 45%. MALDI-TOF mass spectrometry, NMR, UV-vis absorption, steady-state and time-resolved fluorescence spectroscopies have been used to characterize the structures and the spectroscopic/photophysical properties of the obtained dyes.

scholarly journals Effect of Blade Stagger Angle on Performance of a Transonic Compressor With Low Hub-Tip Ratio

1981 ◽  
Author(s):  
Zhao Shi Chun ◽  
Ma Shu Qin ◽  
Wang Zhao Long
Keyword(s):  
Total Pressure ◽  
Pressure Ratio ◽  
Pressure Profile ◽  
Single Stage ◽  
Temperature Profiles ◽  
Transonic Compressor ◽  
Total Temperature ◽  
Design Speed ◽  
Stagger Angle ◽  
Better Than

The effect of blade stagger angle on the performance of a transonic compressor with low hub-tip ratio is presented in the paper. Because the original single stage compressor failed to achieve the design target, tests were conducted on the compressor with the blades twisted and with the stagger angle reduced. The results of these tests indicate that at the design speed and mass flow, the pressure ratio is 1.339, the efficiency is 0.864, which is 2.2 percent better than the design value and 5 percent better than that of the original single stage. At the same time, the discharge total pressure and temperature profiles are improved substantially. The unevenness of the total pressure profile decreases from 18 to 7 percent and that of the total temperature from 53 to 18 percent.

Impact of Rotor–Stator Interaction on Turbine Blade Film Cooling

1996 ◽  
Vol 118 (1) ◽  
pp. 123-133 ◽  
Author(s):  
R. S. Abhari
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Film Cooling ◽  
Numerical Code ◽  
Test Facility ◽  
Time Resolved ◽  
Injection Model ◽  
Rotor Stator Interaction ◽  
The Impact ◽  
State Case

The goal of this study is to quantify the impact of rotor–stator interaction on surface heat transfer of film cooled turbine blades. In Section I, a steady-state injection model of the film cooling is incorporated into a two-dimensional, thin shear layer, multiblade row CFD code. This injection model accounts for the penetration and spreading of the coolant jet, as well as the entrainment of the boundary layer fluid by the coolant. The code is validated, in the steady state, by comparing its predictions to data from a blade tested in linear cascade. In Section II, time-resolved film cooled turbine rotor heat transfer measurements are compared with numerical predictions. Data were taken on a fully film cooled blade in a transonic, high pressure ratio, single-stage turbine in a short duration turbine test facility, which simulates full-engine nondimensional conditions. Film cooled heat flux on the pressure surface is predicted to be as much as a factor of two higher in the time average of the unsteady calculations compared to the steady-state case. Time-resolved film cooled heat transfer comparison of data to prediction at two spanwise positions is used to validate the numerical code. The unsteady stator–rotor interaction results in the pulsation of the coolant injection flow out of the film holes with large-scale fluctuations. The combination of pulsating coolant flow and the interaction of the coolant with this unsteady external flow is shown to lower the local pressure side adiabatic film effectiveness by as much as 64 percent when compared to the steady-state case.

Design and Pre-Test Evaluation of a Low-Pressure Compressor Test Facility for Cryogenic Hydrogen Fuel Integration

2021 ◽  
Author(s):  
Isak Jonsson ◽  
Carlos Xisto ◽  
Marcus Lejon ◽  
Anders Dahl ◽  
Tomas Grönstedt
Keyword(s):  
High Speed ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Aviation Fuel ◽  
Evaluation Methodology ◽  
Test Facility ◽  
Test Evaluation ◽  
Performance Parameters ◽  
Compression Process ◽  
Transonic Compressor

Abstract The use of hydrogen as aviation fuel is again resurfacing with unprecedented vigor. It is well known that hydrogen is a formidable heat sink and the use of heat sinks in the compression system of an aero engine may enable not only preheating of the fuel but also improve the gas turbine cycle itself. One such opportunity arises from extracting heat to the fuel as part of the compression process. This work presents the design process and pre-test evaluation of a low-speed compressor test facility dedicated to aerothermal measurements. The design has been derived from a high-speed transonic compressor developed for a large sized geared turbofan engine. The proposed pre-test evaluation methodology provides a comprehensive and affordable way to estimate facility accuracy by virtually addressing all the experimental procedures, from data acquisition to a final performance map. The evaluation of gathering compressor performance parameters via a gas-path investigation process was achieved while relying on results from numerical simulations. The pre-test evaluation details uncertainties introduced throughout this process with transducers, flow and probe specific errors, traverse discretization, and data normalization. A suitable instrumentation configuration is presented which shows that the performance parameters pressure ratio (Π) and isentropic efficiency (ηc) can be determined with uncertainties below 1% for most operating conditions and below 0.5% at design conditions.

Experimental and Numerical Analysis of Axial Skewed Slot Casing Treatments for a Transonic Compressor Stage

2009 ◽  
Author(s):  
Florian C. T. Danner ◽  
Hans-Peter Kau ◽  
Martin M. Mu¨ller ◽  
Heinz-Peter Schiffer ◽  
Giovanni A. Brignole
Keyword(s):  
Total Pressure ◽  
Pressure Ratio ◽  
Computational Domain ◽  
Compressor Stage ◽  
Time Resolved ◽  
Transonic Compressor ◽  
Computational Fluid Dynamics Analysis ◽  
Grid Points ◽  
Casing Treatments ◽  
Total Pressure Ratio

An investigation of a single-stage transonic compressor with axial skewed slot casing treatments is presented. The studied compressor stage is characterised by a design mass flow rate of 16 kg/s at a total pressure ratio of 1.5 and a rotor tip speed of 400m/s. The research comprises experimental measurements as well as time-resolved simulations at full and part speed. Total pressure ratio measurements and efficiency speedlines are complemented by traversing downstream of the stator and static pressure measurements at the rotor end wall. The experimental work is supported by unsteady computational fluid dynamics analysis to provide further insight into the ruling flow phenomena. The simulations were carried out fully three-dimensionally in a computational domain with approximately 4.8 million grid points including the cavity mesh. The application of the axial skewed slots led to both, an enhanced operating range and an increased design point efficiency. Rises in total pressure ratio along the entire speed lines were observed.

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