Air Splits Research of Multi-Sector Combustor With Flow Network Approach and Experiments

2019 ◽  
Author(s):  
Shanping Shen ◽  
Guoqian Song
Keyword(s):  
Pressure Drop ◽  
Pressure Loss ◽  
Effective Area ◽  
Network Approach ◽  
Test Rig ◽  
Flow Network ◽  
Wide Range ◽  
Aero Engine ◽  
Annular Combustor ◽  
Good Agreement

Abstract Multi-sector combustor tests are essential to aero-engine annular combustor development. For the test rig design, it is necessary to ensure that the pressure drop and flow split to the various portions of multi-sector combustor are consistent with the combustor component. This paper introduces a new kind of multi-sector combustor rig. The diffuser system of the test rig is different with the combustor component. This test rig is simple in structure and easy to machine. To evaluate the flow split and pressure drop of the test rig, a 1D-flow network approach is applied to multi-sector combustor rig design. The calculated results show good agreement with the experiment data. In order to study whether the test rig can simulate flow split and pressure loss of combustor components, flow split and pressure loss under different design features are analyzed. Result shows that by changing the effective area of inner/outer annular inlet baffle and inner/outer bleed air plate, inner/outer liner pressure drop and the ratio of air flow to W31c can be changed in a wide range. Thus, this kind of multi-sector combustor rig is convenient to change the multi-sector combustor test rig design to meet the requirements of the pressure drop and flow split design of combustor component, even when the rig has been manufactured.

Aerodynamic Similarity Principles and Scaling Laws for Windmilling Fans

2018 ◽  
Author(s):  
Dilip Prasad
Keyword(s):  
Rotational Speed ◽  
Pressure Loss ◽  
Scaling Laws ◽  
Dynamic Pressure ◽  
Stagnation Pressure ◽  
Design Parameters ◽  
Similarity Parameter ◽  
Wide Range ◽  
Simulation Results ◽  
Good Agreement

Windmilling requirements for aircraft engines often define propulsion and airframe design parameters. The present study is focused is on two key quantities of interest during windmill operation: fan rotational speed and stage losses. A model for the rotor exit flow is developed, that serves to bring out a similarity parameter for the fan rotational speed. Furthermore, the model shows that the spanwise flow profiles are independent of the throughflow, being determined solely by the configuration geometry. Interrogation of previous numerical simulations verifies the self-similar nature of the flow. The analysis also demonstrates that the vane inlet dynamic pressure is the appropriate scale for the stagnation pressure loss across the rotor and splitter. Examination of the simulation results for the stator reveals that the flow blockage resulting from the severely negative incidence that occurs at windmill remains constant across a wide range of mass flow rates. For a given throughflow rate, the velocity scale is then shown to be that associated with the unblocked vane exit area, leading naturally to the definition of a dynamic pressure scale for the stator stagnation pressure loss. The proposed scaling procedures for the component losses are applied to the flow configuration of Prasad and Lord (2010). Comparison of simulation results for the rotor-splitter and stator losses determined using these procedures indicates very good agreement. Analogous to the loss scaling, a procedure based on the fan speed similarity parameter is developed to determine the windmill rotational speed and is also found to be in good agreement with engine data. Thus, despite their simplicity, the methods developed here possess sufficient fidelity to be employed in design prediction models for aircraft propulsion systems.

Aerodynamic Similarity Principles and Scaling Laws for Windmilling Fans

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Dilip Prasad
Keyword(s):  
Rotational Speed ◽  
Pressure Loss ◽  
Scaling Laws ◽  
Dynamic Pressure ◽  
Stagnation Pressure ◽  
Design Parameters ◽  
Similarity Parameter ◽  
Wide Range ◽  
Simulation Results ◽  
Good Agreement

Windmilling requirements for aircraft engines often define propulsion and airframe design parameters. The present study is focused on two key quantities of interest during windmill operation: fan rotational speed and stage losses. A model for the rotor exit flow is developed that serves to bring out a similarity parameter for the fan rotational speed. Furthermore, the model shows that the spanwise flow profiles are independent of the throughflow, being determined solely by the configuration geometry. Interrogation of previous numerical simulations verifies the self-similar nature of the flow. The analysis also demonstrates that the vane inlet dynamic pressure is the appropriate scale for the stagnation pressure loss across the rotor and splitter. Examination of the simulation results for the stator reveals that the flow blockage resulting from the severely negative incidence that occurs at windmill remains constant across a wide range of mass flow rates. For a given throughflow rate, the velocity scale is then shown to be that associated with the unblocked vane exit area, leading naturally to the definition of a dynamic pressure scale for the stator stagnation pressure loss. The proposed scaling procedures for the component losses are applied to the flow configuration of Prasad and Lord (2010). Comparison of simulation results for the rotor-splitter and stator losses determined using these procedures indicates very good agreement. Analogous to the loss scaling, a procedure based on the fan speed similarity parameter is developed to determine the windmill rotational speed and is also found to be in good agreement with engine data. Thus, despite their simplicity, the methods developed here possess sufficient fidelity to be employed in design prediction models for aircraft propulsion systems.

Prediction of the Pressure Distribution for Radial Inflow Between Co-Rotating Discs

1988 ◽  
Author(s):  
John W. Chew ◽  
Robert J. Snell
Keyword(s):  
Pressure Drop ◽  
Pressure Coefficient ◽  
Integral Solution ◽  
Solution Technique ◽  
Quick Method ◽  
Dimensional Parameter ◽  
Rotating Discs ◽  
Wide Range ◽  
Dimensional Parameters ◽  
Good Agreement

The problem of radial inflow between two plane co-rotating discs with the angular velocity of the fluid at inlet equal to that of the discs is considered. An integral solution technique for turbulent flow, based on that of von Karman (1921), is described. Solutions are shown to be in good agreement with most of the available experimental data. For incompressible flow the pressure drop coefficient is a function of just two non-dimensional parameters; the radius ratio for the cavity and a throughflow parameter. For air flows compressibility can be important and an additional non-dimensional parameter is needed. Results for a wide range of conditions are presented graphically. These show the sensitivity of the pressure coefficient to the governing parameters and provide a quick method for estimating the pressure drop.

An Experimental Investigation on the Temperature Distribution in Circular Journal Bearings

1986 ◽  
Vol 108 (4) ◽  
pp. 621-626 ◽  
Author(s):  
Junichi Mitsui ◽  
Yukio Hori ◽  
Masato Tanaka
Keyword(s):  
Experimental Investigation ◽  
Angular Position ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Test Rig ◽  
Clearance Ratio ◽  
Temperature Distributions ◽  
Wide Range ◽  
Lubricant Viscosity ◽  
Good Agreement

The temperature distributions in full circular bearings were measured in a test rig. The effects of journal speed, lubricant viscosity, and clearance ratio on the maximum bearing temperature and its location were discussed. The results were compared with the theoretical analysis by the present authors and good agreement was obtained over the wide range of operating conditions. The maximum bearing temperature is found to increase considerably with the increase of speed or lubricant viscosity and also with the decrease of clearance ratio. Its angular position is found to vary with speed and clearance ratio. These phenomena can be explained by the characteristics of maximum film temperature in the oil film.

Thermal modelling of a back-to-back gearbox test machine: Application to the FZG test rig

2012 ◽  
Vol 226 (6) ◽  
pp. 501-515 ◽  
Author(s):  
J Durand de Gevigney ◽  
C Changenet ◽  
F Ville ◽  
P Velex
Keyword(s):  
Thermal Model ◽  
Thermal Modelling ◽  
Bulk Temperature ◽  
Test Machine ◽  
Network Approach ◽  
Power Losses ◽  
Test Rig ◽  
Isothermal Method ◽  
Transient Regimes ◽  
Good Agreement

A thermal model of a back-to-back gear test rig relying on a network approach is presented in which the predictions of temperatures and power losses are coupled. The numerical findings are in good agreement with the measurements for transient regimes on a FZG test rig and it is demonstrated that the proposed simulation is reliable. A number of results are presented which illustrate the influence of the pinion and gear immersion depths. It is found that, in certain conditions, the classic isothermal method for estimating integral temperatures is questionable because the actual bulk temperature can substantially deviate from that of the oil sump. The practical consequences in terms of scuffing capacity are emphasised.

scholarly journals Experimental study of the pressure loss in aero-engine air-oil separators

2017 ◽  
Vol 121 (1242) ◽  
pp. 1147-1161 ◽  
Author(s):  
A. Laura Cordes ◽  
B. Tim Pychynski ◽  
C. Corina Schwitzke ◽  
D. Hans-Jörg Bauer ◽  
A. Thiago P. de Carvalho ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Pressure Loss ◽  
Metal Foam ◽  
Separation Efficiency ◽  
Air Mass ◽  
Aero Engine

ABSTRACTThe results of extensive experimental testing of an aero-engine air-oil separator are presented and discussed. The study focuses on the pressure loss of the system. Oil enters the device in the form of dispersed droplets. Subsequently, separation occurs by centrifuging larger droplets towards the outer walls and by film formation at the inner surface of a rotating porous material, namely an open-cell metal foam. The work described here is part of a study led jointly by the Karlsruhe Institute of Technology (KIT) and the University of Nottingham (UNott) within a recent EU project.The goal of the research is to increase the separation efficiency to mitigate oil consumption and emissions, while keeping the pressure loss as low as possible. The aim is to determine the influencing factors on pressure loss and separation efficiency. With this knowledge, a correlation can eventually be derived. Experiments were conducted for three different separator configurations, one without a metal foam and two with metal foams of different pore sizes. For each configuration, a variety of engine-like conditions of air mass flow rate, rotational speed and droplet size was investigated. The experimental results were used to validate and improve the numerical modelling.Results for the pressure drop and its dependencies on air mass flow rate and the rotational speed were analysed. It is shown that the swirling flow and the dissipation of angular momentum are the most important contributors to the pressure drop, besides the losses due to friction and dissipation caused by the flow passing the metal foam. It was found that the ratio of the rotor speed and the tangential velocity of the fluid is an important parameter to describe the influence of rotation on the pressure loss. Contrary to expectations, the pressure loss is not necessarily increased with a metal foam installed.

scholarly journals An Efficient Numerical Method for Pressure Loss Investigation in an Oil/Air Separator with Metal Foam in an Aero-Engine

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 346 ◽  
Author(s):  
Lifen Zhang ◽  
Xiaoxue Zhang ◽  
Zhenxia Liu
Keyword(s):  
Porous Media ◽  
Pressure Drop ◽  
Numerical Method ◽  
Working Conditions ◽  
Pressure Loss ◽  
Metal Foam ◽  
Speed Increase ◽  
Rotating Speed ◽  
Aero Engine ◽  
Resistance Coefficients

An efficient method of simulating pressure loss in a separator with metal foam is reported. In this method, a metal foam is modeled as a porous media having homogenized permeability and inertial resistance coefficients. The permeability and inertial resistance coefficients were obtained by a numerical method that was validated by experimental data from a literature. Then the pressure drop in the separator with metal foam replaced by porous media was efficiently simulated under different working conditions, and the results were analyzed. It was found that the porous media had a great effect on the pressure drop in the separator. As pores per inch (PPI) and rotating speed increase and porosity decreases, the pressure drop of the separator increases. The results indicate that replacing metal foam by porous media is effective and simulating the pressure drop is feasible and effective in a separator with metal foam.

On the Numerical Evaluation of Tone Noise Emissions Generated by a Turbine Stage: An In-Depth Comparison Among Different Computational Methods

2015 ◽  
Author(s):  
Lorenzo Pinelli ◽  
Francesco Poli ◽  
Andrea Arnone ◽  
Sébastien Guérin ◽  
Axel Holewa ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Harmonic Balance ◽  
Operating Conditions ◽  
Turbine Stage ◽  
Test Rig ◽  
Propulsion Systems ◽  
Wide Range ◽  
Unsteady Rans ◽  
Processing Techniques ◽  
Good Agreement

Within the European research project RECORD (Research on Core Noise Reduction) the tone noise emissions of a high-pressure turbine stage have been numerically evaluated by six different academic and industrial partners. The turbine stage geometry and operating conditions match an HPT test rig located at Politecnico di Milano (Italy). Since the constant demand for quieter and greener propulsion systems has led to the development of several numerical aeroacoustic codes, this common benchmark represents an important chance to compare the performance of each approach. In this paper, the tone noise results of three distinct categories of numerical solvers (unsteady RANS, harmonic balance and time-linearized approaches) are compared. For the tone noise simulations, all the partners used non-reflecting boundary conditions at the domain inlet and outlet in order to avoid spurious reflections. Moreover, the acoustic modeshapes in the turbine duct were evaluated with different level of complexity by the various partners and different post-processing techniques were employed to extract the acoustic waves from the unsteady solutions. The result comparisons for the blade passing frequency have shown a good agreement (within 4 dB) among the partners in terms of PWL values. Also the acoustic eigenmodes (radial shapes of the pressure waves) and the eigenvalues (axial wave numbers) agree well among the different simulations. A wide range of acoustic results are presented and discussed in the paper.

Derivation of an Anisotropic Model for the Pressure Loss Through a Heat Exchanger for Aero Engine Applications

2009 ◽  
Author(s):  
Kyros Yakinthos ◽  
Stefan Donnerhack ◽  
Dimitrios Missirlis ◽  
Olivier Seite ◽  
Paul Storm
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Pressure Loss ◽  
Pollutant Emissions ◽  
Experimental Measurements ◽  
Loss Model ◽  
Aero Engine ◽  
Porosity Model

We present an effort to model the pressure loss together with the heat transfer mechanism, in a heat exchanger designed for an integrated recuperative aero engine. The operation of the heat exchanger is focusing on the exploitation of the thermal energy of the turbine exhaust gas to pre-heat the compressor outlet air before combustion and to decrease fuel consumption and pollutant emissions. Two basic parameters characterize the operation of the heat exchanger, the pressure loss and the heat transfer. The derivation of the pressure loss model is based on experimental measurements that have been carried-out on a heat exchanger model. The presence of the heat exchanger is modeled using the concept of a porous medium, in order to facilitate the computational modeling by means of CFD. As a result, inside the integrated aero engine, the operation of the heat exchanger can be sufficiently modeled as long as a generalized and accurate pressure drop and heat transfer model is developed. Hence, the porosity model formulation should be capable of properly describing the overall macroscopic hydraulic and thermal behavior of the heat exchanger. The effect of the presence of the heat exchanger on the flow field is estimated from experimental measurements. For the derivation of the porous medium pressure loss model, an anisotropic formulation of a modified Darcy-Forchheimer pressure drop law is proposed in order to take into account the effects of the three-dimensional flow development through the heat exchanger. The heat transfer effects are taken also into account with the use of a heat transfer coefficient correlation. The porosity model is adopted by the CFD solver as an additional source term. The validation of the proposed model is performed through CFD computations, by comparing the predicted pressure drop and heat transfer with available experimental measurements carried-out on the heat exchanger model.

A Model to Predict Stratification in Two Phase Flow in Horizontal Pipes

2004 ◽  
Author(s):  
Rajnish K. Calay ◽  
Ahmad Awad
Keyword(s):  
Pressure Drop ◽  
Phase Flow ◽  
Two Phase ◽  
Horizontal Pipes ◽  
Wide Range ◽  
Flow Field Characteristics ◽  
The Cost ◽  
Drop Water ◽  
Cost Of Transportation ◽  
Good Agreement

Stratified flow is encountered in many situations. The flow of hydrocarbons transported in horizontal pipes often gets stratified. The prediction of pressure drop and liquid hold-up is essential for reservoir and pipe management and optimizing the cost of transportation of constituents. The present paper presents a simple mathematical model to predict the pressure drop, water and oil hold up and stratified layer. A good agreement with the experimental data was found. The model will be further developed and incorporated within a numerical model in order to investigate the flow field characteristics and establish correlations for a wide range of parameters.

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