1/4 Scale Hot Flow Model Test of a GE LM2500 Exhaust System

1992 ◽  
Author(s):  
D. Vandam ◽  
A. M. Birk
Keyword(s):  
System Performance ◽  
Flow Model ◽  
Static Pressure ◽  
Exhaust System ◽  
Engine Exhaust ◽  
Static Pressure Distribution ◽  
Sample Data ◽  
Infrared Signature ◽  
Mass Flow Rates ◽  
Cooling Air

A facility has been constructed to test exhaust systems for the GE LM2500 Gas Turbine. The facility is capable of simulating the hot flow exhaust conditions for the LM2500 in 1/4 scale. The facility was constructed to study LM2500 exhaust system performance including the effects of small changes in the geometry of the LM2500 exhaust collector and also to study the effects of devices such as infrared signature suppressors on the overall exhaust system performance. The facility is currently instrumented to measure local static and total pressures, local swirl angles, exit plane total and static pressure distribution, and primary (engine exhaust) and secondary (enclosure cooling air) mass flow rates. The facility has been constructed to accommodate a variety of exhaust uptake geometries. Tests were recently conducted to study certain aspects of exhaust system performance. Sample data is presented and comparisons are made with other available data.

An Investigation of Flow Characteristics and Parameter Effects for a New Concept of Hybrid SVC Nozzle

2018 ◽  
Author(s):  
F. Song ◽  
J. W. Shi ◽  
L. Zhou ◽  
Z. X. Wang ◽  
X. B. Zhang
Keyword(s):  
Static Pressure ◽  
Pressure Ratio ◽  
Flow Characteristics ◽  
Exhaust System ◽  
Aircraft Engine ◽  
Thrust Coefficient ◽  
Thrust Vectoring ◽  
Static Pressure Distribution ◽  
Thrust Vector ◽  
Vector Angle

Lighter weight, simpler structure, higher vectoring efficiency and faster vector response are recent trends in development of aircraft engine exhaust system. To meet these new challenges, a concept of hybrid SVC nozzle was proposed in this work to achieve thrust vectoring by adopting a rotatable valve and by introducing a secondary flow injection. In this paper, we numerically investigated the flow mechanism of the hybrid SVC nozzle. Nozzle performance (e.g. the thrust vector angle and the thrust coefficient) was studied with consideration of the influence of aerodynamic and geometric parameters, such as the nozzle pressure ratio (NPR), the secondary pressure ratio (SPR) and the deflection angle of the rotatable valve (θ). The numerical results indicate that the introductions of the rotatable valve and the secondary injection induce an asymmetrically distributed static pressure to nozzle internal walls. Such static pressure distribution generates a side force on the primary flow, thereby achieving thrust vectoring. Both the thrust vector angle and vectoring efficiency can be enhanced by reducing NPR or by increasing θ. A maximum vector angle of 16.7 ° is attained while NPR is 3 and the corresponding vectoring efficiency is 6.33 °/%. The vector angle first increases and then decreases along with the elevation of SPR, and there exists an optimum value of SPR for maximum thrust vector angle. The effects of θ and SPR on the thrust coefficient were found to be insignificant. The rotatable valve can be utilized to improve vectoring efficiency and to control the vector angle as expected.

Rim Seal Experiments and Analysis of a Rotor-Stator System With Nonaxisymmetric Main Flow

1992 ◽  
Author(s):  
K. Hamabe ◽  
K. Ishida
Keyword(s):  
Static Pressure ◽  
Main Flow ◽  
Test Results ◽  
Gas Concentration ◽  
Static Pressure Distribution ◽  
Precise Prediction ◽  
Cooling Air Flow ◽  
Shrouded Rotor ◽  
Cooling Air ◽  
Good Agreement

To examine the simplified model to predict the ingress flow rate which was formerly proposed by the authors, the scaling characteristics of a shrouded rotor-stator system with a nonaxisymmetric main flow is studied using gas concentration measurements in the wheel-space. The predicted value for the sealing effectiveness as well as the minimum cooling air flow ratio necessary to prevent ingress is shown to be relatively in good agreement with the test results. It is also found that for the precise prediction of the sealing effectiveness, the circumferential static pressure distribution in the annulus is needed.

Static pressure distribution in the free turbulent jet

1957 ◽  
Vol 3 (1) ◽  
pp. 1-16 ◽  
Author(s):  
David R. Miller ◽  
Edward W. Comings
Keyword(s):  
Static Pressure ◽  
Longitudinal Velocity ◽  
Fluid Motion ◽  
Mean Velocity ◽  
Free Jet ◽  
Static Pressure Distribution ◽  
Two Dimensional Flow ◽  
The Common ◽  
Jet Theory ◽  
Made In

Measurements of mean velocity, turbulent stress and static pressure were made in the mixing region of a jet of air issuing from a slot nozzle into still air. The velocity was low and the two-dimensional flow was effectively incompressible. The results are examined in terms of the unsimplified equations of fluid motion, and comparisons are drawn with the common assumptions and simplifications of free jet theory. Appreciable deviations from isobaric conditions exist and the deviations are closely related to the local turbulent stresses. Negative static pressures were encountered everywhere in the mixing field except in the potential wedge region immediately adjacent to the nozzle. Lateral profiles of mean longitudinal velocity conformed closely to an error curve at all stations further than 7 slot widths from the nozzle mouth. An asymptotic approach to complete self-preservation of the flow was observed.

Ingestion Into the Upstream Wheelspace of an Axial Turbine Stage

1994 ◽  
Vol 116 (2) ◽  
pp. 327-332 ◽  
Author(s):  
T. Green ◽  
A. B. Turner
Keyword(s):  
Pressure Distribution ◽  
Static Pressure ◽  
Three Dimensional ◽  
Computer Code ◽  
Rotor Blades ◽  
Rotor Speed ◽  
Turbine Stage ◽  
Flow Rates ◽  
Static Pressure Distribution ◽  
Axial Clearance

The upstream wheelspace of an axial air turbine stage complete with nozzle guide vanes (NGVs) and rotor blades (430 mm mean diameter) has been tested with the objective of examining the combined effect of NGVs and rotor blades on the level of mainstream ingestion for different seal flow rates. A simple axial clearance seal was used with the rotor spun up to 6650 rpm by drawing air through it from atmospheric pressure with a large centrifugal compressor. The effect of rotational speed was examined for several constant mainstream flow rates by controlling the rotor speed with an air brake. The circumferential variation in hub static pressure was measured at the trailing edge of the NGVs upstream of the seal gap and was found to affect ingestion significantly. The hub static pressure distribution on the rotor blade leading edges was rotor speed dependent and could not be measured in the experiments. The Denton three-dimensional C.F.D. computer code was used to predict the smoothed time-dependent pressure field for the rotor together with the pressure distribution downstream of the NGVs. The level and distribution of mainstream ingestion, and thus the seal effectiveness, was determined from nitrous oxide gas concentration measurements and related to static pressure measurements made throughout the wheelspace. With the axial clearance rim seal close to the rotor the presence of the blades had a complex effect. Rotor blades in connection with NGVs were found to reduce mainstream ingestion seal flow rates significantly, but a small level of ingestion existed even for very high levels of seal flow rate.

scholarly journals Performance Assessment of an Annular S-Shaped Duct

1995 ◽  
Author(s):  
D. W. Bailey ◽  
K. M. Britchford ◽  
J. F. Carrotte ◽  
S. J. Stevens
Keyword(s):  
Shear Stress ◽  
Static Pressure ◽  
Compressor Blade ◽  
Turbine Engines ◽  
Pressure Gradients ◽  
Gas Turbine Engines ◽  
Entry Length ◽  
Static Pressure Distribution ◽  
Flow Curvature ◽  
Inlet Conditions

An experimental investigation has been carried out to determine the aerodynamic performance of an annular S-shaped duct representative of that used to connect the compressor spools of aircraft gas turbine engines. For inlet conditions in which boundary layers are developed along an upstream entry length the static pressure, shear stress and velocity distributions are presented. The data shows that as a result of flow curvature significant streamwise pressure gradients exist within the duct, with this curvature also affecting the generation and suppression of turbulence. The stagnation pressure loss within the duct is also assessed and is consistent with the measured distributions of shear stress. More engine representative conditions are provided by locating a single stage compressor at inlet to the duct. Relative to the naturally developed inlet conditions the flow within the duct is less likely to separate, but mixing out of the compressor blade wakes increases the measured duct loss. With both types of inlet conditions the effect of a radial strut, such as that used for carrying loads and engine services, is also described both in terms of the static pressure distribution along the strut and its contribution to overall loss.

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