Lube Oil and Bearing Thermal Management System

2009 ◽  
Author(s):  
Karleine M. Justice ◽  
Jeffrey S. Dalton ◽  
Ian Halliwell ◽  
Stephen Williamson
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Thermal Management ◽  
Gas Turbine Engine ◽  
System Level ◽  
Engine Oil ◽  
Management Systems ◽  
Lubrication System ◽  
Turbine Engine ◽  
Heat Loads

Recent improvements in technology have enabled the development of models capable of capturing performance interactions in the thermal management of air vehicle systems. Such system level models are required for better understanding of integration constraints and interactions, and are becoming increasingly important because of the need for tighter coupling between the components of thermal management systems. The study described here integrates current engine modeling capabilities with an improved, more comprehensive thermal management simulation. More specifically, the current effort evaluates the heat loads associated with the lubrication system of a gas turbine engine. The underlying engine model represents a mid-size, two-spool, subsonic transport engine. The architecture of the model is adaptable to other two-spool turbine engines and missions. Mobil Avrex S Turbo 256 engine oil is used as the lubrication medium. The model consists of five bearing heat loads. Within the engine flowpath, local temperatures and the appropriate rotational speeds are the only parameters pertinent to the heat load calculations. General assumptions have been made to simplify the representation of the lubrication system. Fuel properties into the heat exchanger are assumed. A gear box attached to the high-speed shaft operates both supply pump and scavenge pump and sends compressed air to the oil reservoir. Once the oil is distributed to the bearings, the scavenge pump collects and sends it through a filter and a fuel/oil heat exchanger before it is remixed with the contents of the reservoir. A MATLAB/Simulink modeling environment provides a general approach that may be applied to the thermal management of any engine. As a result of this approach, the new model serves as a starting point for a flexible architecture that can be modified as more detailed specifications or data are made available. In this paper, results from the simple model are compared to a more comprehensive tribology-based analysis. The results demonstrate its successful application to a typical mission, based on very limited data. In general, these results will allow system designers to conduct preliminary analyses and trade studies of gas turbine engine thermal management systems.

A Simple Thermal Model of Bearings With Transient Effects

2010 ◽  
Author(s):  
Karleine M. Justice ◽  
Ian Halliwell ◽  
Jeffrey S. Dalton
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Thermal Management ◽  
Heat Load ◽  
Transient Behavior ◽  
Gas Turbine Engine ◽  
System Level ◽  
Lubrication System ◽  
Transient Effects ◽  
Turbine Engine

In thermal management, system-level models provide an understanding of interactions between components and integration constraints — issues which are exacerbated by tighter coupling in both real life and simulation. A simple model of the steady-state thermal characteristics of the bearings in a two-spool turbofan engine has been described in previous work [1], where it was compared with a more comprehensive tribology-based simulation. Since failure is more likely to occur during transient rather than steady-state operating conditions, it is important that transient behavior is also studied. Therefore, development of models capable of capturing transient system-level performance in air vehicles is critical. In the current paper, the former simple model is used for the generation of a method to replicate the transient effects of heat loads within the lubrication system of a gas turbine engine. The simple engine model that defined the lubrication system is representative of a twin-spool, mid-size, high bypass ratio turbofan used in commercial transport. In order to demonstrate the range and versatility of the parametric heat load model, the model is now applied to the transient operation of a low-thrust unmanned aerial vehicle (UAV) engine, similar to that found on the Global Hawk. There are five separate bearings in the oil loop model and four separate oil sump locations. Contributions to the heat load calculations are heat transfer through the bearing housings and friction caused by station temperatures and shaft speeds, respectively. The lubrication system has been simplified by applying general assumptions for a proof-of-concept of the new transient parametric model. The fuel flow rate for the fuel-cooled oil cooler (FCOC) is set via the full authority digital electronic control (FADEC) in the transient engine model which is coupled to the parametric heat load model. Initially, it is assumed that total heat transfer from the bearings to the oil correspond to oil temperature changes of 150–250°F (83–139°C). The results show that successful modeling of the transient behavior on the thermal effects in the bearings of a gas turbine engine using the MATLAB/Simulink environment have been achieved. This is a valuable addition to the previous steady-state simulation, and the combined tools may be used as part of a more sophisticated thermal management system. Because it is so simple and scalable, the tool enables thermal management issues to be addressed in the preliminary design phase of a gas turbine engine development program.

scholarly journals The effect of heat recovery on the optimal values of helicopter turboshaft engine parameters

2020 ◽  
Vol 19 (4) ◽  
pp. 43-57
Author(s):  
H. H. Omar ◽  
V. S. Kuz'michev ◽  
A. O. Zagrebelnyi ◽  
V. A. Grigoriev
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Heat Recovery ◽  
Thermodynamic Cycle ◽  
Gas Turbine Engine ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Working Process ◽  
Turbine Engine ◽  
Recuperative Heat Exchanger

Recent studies related to fuel economy in air transport conducted in our country and abroad show that the use of recuperative heat exchangers in aviation gas turbine engines can significantly, by up to 20...30%, reduce fuel consumption. Until recently, the use of cycles with heat recovery in aircraft gas turbine engines was restrained by a significant increase in the mass of the power plant due to the installation of a heat exchanger. Currently, there is a technological opportunity to create compact, light, high-efficiency heat exchangers for use on aircraft without compromising their performance. An important target in the design of engines with heat recovery is to select the parameters of the working process that provide maximum efficiency of the aircraft system. The article focused on setting of the optimization problem and the choice of rational parameters of the thermodynamic cycle parameters of a gas turbine engine with a recuperative heat exchanger. On the basis of the developed method of multi-criteria optimization the optimization of thermodynamic cycle parameters of a helicopter gas turbine engine with a ANSAT recuperative heat exchanger was carried out by means of numerical simulations according to such criteria as the total weight of the engine and fuel required for the flight, the specific fuel consumption of the aircraft for a ton- kilometer of the payload. The results of the optimization are presented in the article. The calculation of engine efficiency indicators was carried out on the basis of modeling the flight cycle of the helicopter, taking into account its aerodynamic characteristics. The developed mathematical model for calculating the mass of a compact heat exchanger, designed to solve optimization problems at the stage of conceptual design of the engine and simulation of the transport helicopter flight cycle is presented. The developed methods and models are implemented in the ASTRA program. It is shown that optimal parameters of the working process of a gas turbine engine with a free turbine and a recuperative heat exchanger depend significantly on the heat exchanger effectiveness. The possibility of increasing the efficiency of the engine due to heat regeneration is also shown.

Regenerator Development for the British Leyland 2S/350/R Gas Turbine Engine

1974 ◽  
Author(s):  
J. A. Ritchie ◽  
P. A. Phillips ◽  
M. C. S. Barnard
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Turbine Engine ◽  
Single Disk

This paper describes the application of the ceramic regenerator to the British Leyland truck gas turbine. Aspects of mounting, driving and sealing the heat exchanger disk are covered with particular reference to the single disk version of the 2S/350/R engine.

Investigation of Vapor-Phase Lubrication in a Gas Turbine Engine

1997 ◽  
Author(s):  
Kenneth W. Van Treuren ◽  
D. Neal Barlow ◽  
William H. Heiser ◽  
Matthew J. Wagner ◽  
Nelson H. Forster
Keyword(s):  
Gas Turbine ◽  
Vapor Phase ◽  
Gas Turbine Engine ◽  
Rolling Contact ◽  
Phosphate Ester ◽  
Lubrication System ◽  
Oil Lubrication ◽  
Vapor Phase Lubrication ◽  
Engine Operation ◽  
Turbine Engine

The liquid oil lubrication system of current aircraft jet engines accounts for approximately 10–15% of the total weight of the engine. It has long been a goal of the aircraft gas turbine industry to reduce this weight. Vapor-Phase Lubrication (VPL) is a promising technology to eliminate liquid oil lubrication. The current investigation resulted in the first gas turbine to operate in the absence of conventional liquid lubrication. A phosphate ester, commercially known as DURAD 620B, was chosen for the test. Extensive research at Wright Laboratory demonstrated that this lubricant could reliably lubricate railing element bearings in the gas turbine engine environment. The Allison T63 engine was selected as the test vehicle because of its small size and bearing configuration. Specifically, VPL was evaluated in the number eight bearing because it is located in a relatively hot environment, in line with the combustor discharge, and it can be isolated from the other bearings and the liquid lubrication system. The bearing was fully instrumented and its performance with standard oil lubrication was documented. Results of this baseline study were used to develop a thermodynamic model to predict the bearing temperature with VPL. The engine was then operated at a ground idle condition with VPL with the lubricant misted into the #8 bearing at 13 ml/hr. The bearing temperature stabilized at 283°C within 10 minutes. Engine operation was continued successfully for a total of one hour. No abnormal wear of the rolling contact surfaces was found when the bearing was later examined. Bearing temperatures after engine shutdown indicated the bearing had reached thermodynamic equilibrium with its surroundings during the test. After shutdown bearing temperatures steadily decreased without the soakback effect seen after shutdown in standard lubricated bearings. In contrast, the oil lubricated bearing ran at a considerably lower operating temperature (83°C) and was significantly heated by its surroundings after engine shutdown. In the baseline tests, the final bearing temperatures never reached that of the operating VPL system.

scholarly journals Analysis of NOx Formation in a Hydrogen Fueled Gas Turbine Engine

2008 ◽  
Author(s):  
Peter Therkelsen ◽  
Tavis Werts ◽  
Vincent McDonell ◽  
Scott Samuelsen
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Full Range ◽  
Gas Turbine Engine ◽  
System Level ◽  
Stable Operation ◽  
No Production ◽  
No Emission ◽  
Nox Formation ◽  
Turbine Engine

A commercially available natural gas fueled gas turbine engine was operated on hydrogen. Three sets of fuel injectors were developed to facilitate stable operation while generating differing levels of fuel/air premixing. One set was designed to produce near uniform mixing while the others have differing degrees of non-uniformity. The emissions performance of the engine over its full range of loads is characterized for each of the injector sets. In addition, the performance is also assessed for the set with near uniform mixing as operated on natural gas. The results show that improved mixing and lower equivalence ratio decreases NO emission levels as expected. However, even with nearly perfect premixing, it is found that the engine, when operated on hydrogen, produces a higher amount of NO than when operated with natural gas. Much of this attributed to the higher equivalence ratios that the engine operates on when firing hydrogen. However, even at the lowest equivalence ratios run at low power conditions, higher NO was observed. Analysis of the potential NO formation effects of residence time, kinetic pathways of NO production via NNH, and the kinetics of the dilute combustion strategy used are evaluated. While no one mechanism appears to explain the reasons for the higher NO, it is concluded that each may be contributing to the higher NO emissions observed with hydrogen. In the present configuration with the commercial control system operating normally, it is evident that system level effects are also contributing to the observed NO emission differences between hydrogen and natural gas.

Fabrication and Performance of a Pin Fin Micro Heat Exchanger

2004 ◽  
Vol 126 (3) ◽  
pp. 434-444 ◽  
Author(s):  
Christophe Marques ◽  
Kevin W. Kelly
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Heat Exchangers ◽  
Turbine Blades ◽  
High Heat ◽  
Gas Turbine Engine ◽  
High Heat Flux ◽  
Turbine Engine ◽  
Pin Fin ◽  
Micro Heat Exchanger

Nickel micro pin fin heat exchangers can be electroplated directly onto planar or non-planar metal surfaces using a derivative of the LIGA micromachining process. These heat exchangers offer the potential to more effectively control the temperature of surfaces in high heat flux applications. Of particular interest is the temperature control of gas turbine engine components. The components in the gas turbine engine that require efficient, improved cooling schemes include the gas turbine blades, the stator vanes, the turbine disk, and the combustor liner. Efficient heating of component surfaces may also be required (i.e., surfaces near the compressor inlet to prevent deicing). In all cases, correlations providing the Nusselt number and the friction factor are needed for such micro pin fin heat exchangers. Heat transfer and pressure loss experimental results are reported for a flat parallel plate pin fin micro heat exchanger with a staggered pin fin array, with height-to-diameter ratios of 1.0, with spacing-to-diameter ratios of 2.5 and for Reynolds numbers (based on the hydraulic diameter of the channel) from 4000 to 20,000. The results are compared to studies of larger scale, but geometrically similar, pin fin heat exchangers. To motivate further research, an analytic model is described which uses the empirical results from the pin fin heat exchanger experiments to predict a cooling effectiveness exceeding 0.82 in a gas turbine blade cooling application. As a final point, the feasibility of fabricating a relatively complex micro heat exchanger on a simple airfoil (a cylinder) is demonstrated.

Conditions for Scuffing Failure of Ground and Superfinished Steel Disks at High Sliding Speeds Using a Gas Turbine Engine Oil

1995 ◽  
Vol 117 (3) ◽  
pp. 482-489 ◽  
Author(s):  
M. J. Patching ◽  
C. C. Kweh ◽  
H. P. Evans ◽  
R. W. Snidle
Keyword(s):  
Experimental Investigation ◽  
Gas Turbine ◽  
Surface Finish ◽  
Axial Direction ◽  
Gas Turbine Engine ◽  
Hardened Steel ◽  
Engine Oil ◽  
Turbine Engine ◽  
Involute Gears ◽  
Scuffing Failure

This paper describes the results of an experimental investigation to compare the scuffing performance of conventionally ground and superfinished hardened steel disks operating at sliding speeds of up to 26 m/s and lubricated with a gas turbine engine oil at a temperature of 100° C. The ground disks were finished in the axial direction to simulate the orientation of surface finish found on involute gears. Superfinishing was found to give a significant increase in the load at which scuffing occurred. Frictional traction was also measured in the experiments and was found to be significantly lower for the superfinished disks in the loading stages preceding scuffing failure.

Rotary Regenerators for the Whirlfire Vehicular Turbines

1959 ◽  
Author(s):  
Paul T. Vickers
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Pressure Loss ◽  
Gas Turbine Engine ◽  
General Motors ◽  
Design And Development ◽  
Turbine Engine ◽  
Performance Results

The major considerations in the selection, design and development of a rotary regenerator for a vehicular gas turbine are discussed. The performance results, such as effectiveness, pressure loss and leakage of the regenerator in the General Motors Research GT-305 gas-turbine engine are presented in detail. A method for evaluating new heat-exchanger surfaces and the techniques used in developing the regenerator are also included.

Design of a Carbon-Carbon Finned Surface Heat Exchanger for a High-Bypass Ratio, High Speed Gas Turbine Engine

2006 ◽  
Author(s):  
Tom Filburn ◽  
Amanda Kloter ◽  
Dave Cloud
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Carbon Composites ◽  
Numerical Estimation ◽  
Turbine Engine ◽  
Conductive Materials ◽  
Final Design ◽  
Finned Surface

Compact heat exchanger designs are commonly used in many gas turbine engine applications. Though effective in their heat transfer function, they are often heavy, costly, and poor aerodynamic performers causing a reduction in engine efficiency. In addition, they are complex to manufacture and often prone to leakage. Finned surface heat exchangers are an attractive alternative to traditional compact designs. They can perform efficiently both aerodynamically and thermally. Such units could be mounted in the bypass fan stream of a gas turbine engine where large amounts of heat must be rejected from vital engine fluids such as oil and fuel. This research project investigated the efficiency of various fin designs applied to an oil cooler. Highly conductive materials, such as carbon composites were explored, and then compared to aerospace-quality aluminum alloys. Thermal, aerodynamic, economic, and weight performance comparisons between the carbon and aluminum fin structures were quantified. A three-dimensional numerical estimation of the final design concept was conducted using ANSYS. This research project specifically investigated the design of a finned surface air-oil heat exchanger. Design parameters included a total heat rejection of 2000 Btu/min and an oil temperature change of 100 degrees Fahrenheit with an inlet oil temperature of 300 degrees. The first design phase was conducted using an aerospace quality aluminum alloy. Internal and external flow convection theory was studied closely as well as basic heat exchanger and fin design concepts. A heat exchanger program was developed in Excel, automating the heat transfer based on basic geometric inputs. The program allowed easy iterations of fin/oil passage designs to meet the performance requirements and optimize the heat exchanger’s weight. The final iteration was then numerically modeled in ANSYS. The predicted heat transfer rate was then compared to the numerical estimation in ANSYS. The Excel program was validated by producing results within 2% of the ANSYS predicted solutions. Upon completion of the aluminum design. highly conductive materials, such as carbon composites were explored and implemented. The final designs of this project (both Aluminum and Carbon-Carbon) identified a new method of heat rejection at a significantly lower weight impact to the engine. The aluminum design had a total core weight of 25.4 lb while the carbon-carbon final design had a total core weight of 12.8 lb. In addition, both units have the potential to be incorporated within an existing engine case exposed to the bypass air stream, which may result in an additional weight savings.

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