Study on Accuracy of Heat Transfer Coefficient Determination in the Bearing Chamber for Gas Turbine Engine

2020 ◽  
Author(s):  
Illia Petukhov ◽  
Taras Mykhailenko ◽  
Sergiy Yepifanov ◽  
Oleg Shevchuk
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Gas Turbine ◽  
Experimental Studies ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Cooling Medium ◽  
External Cooling

Abstract The heat transfer coefficient (HTC) is one of the key parameters that should be known at the stage of the bearing chamber design. This ensures safe temperature conditions for the lubrication oil and reliable operation of the gas turbine engine. The temperature gradient method is commonly used in experimental practice to determinate the HTC. The accuracy of the HTC determination is sensitive to changing of the bearing chamber operating conditions and should be analyzed at the stage of experimental studies planning. This paper presents a study on the accuracy of HTC determination when the external cooling of the bearing chamber is used to obtain the temperature difference sufficient for measurement. Three ways to reduce the relative error of the HTC determination in the bearing chamber were analyzed: i) decreasing the temperature measurement error; ii) decreasing the temperature of external cooling medium; iii) increasing the external heat transfer coefficient and contribution of wall thermal resistance optimization. For different operating conditions of the bearing chamber, the temperature of the outer wall that ensures the specified accuracy of the experimental HTC and the required parameters of the cooling medium were determined and recommended for practical implementation.

The Effect of Heat Transfer Coefficient Increase on Tip Clearance Control in H.P. Compressors in Gas Turbine Engine

2013 ◽  
Author(s):  
Godwin Ita Ekong ◽  
Christopher A. Long ◽  
Peter R. N. Childs
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Gas Turbine ◽  
Time Constant ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Test Facility ◽  
Turbine Engine

Compressor tip clearance for a gas turbine engine application is the radial gap between the stationary compressor casing and the rotating blades. The gap varies significantly during different operating conditions of the engine due to centrifugal forces on the rotor and differential thermal expansions in the discs and casing. The tip clearance in the axial flow compressor of modern commercial civil aero-engines is of significance in terms of both mechanical integrity and performance. In general, the clearance is of critical importance to civil airline operators and their customers alike because as the clearance between the compressor blade tips and the casing increases, the aerodynamic efficiency will decrease and therefore the specific fuel consumption and operating costs will increase. This paper reports on the development of a range of concepts and their evaluation for the reduction and control of tip clearance in H.P. compressors using an enhanced heat transfer coefficient approach. This would lead to improvement in cruise tip clearances. A test facility has been developed for the study at the University of Sussex, incorporating a rotor and an inner shaft scaled down from a Rolls-Royce Trent aero-engine to a ratio of 0.7:1 with a rotational speed of up to 10000 rpm. The idle and maximum take-off conditions in the square cycle correspond to in-cavity rotational Reynolds numbers of 3.1×106 ≤ Reφ ≤ 1.0×107. The project involved modelling of the experimental facilities, to demonstrate proof of concept. The analysis shows that increasing the thermal response of the high pressure compressor (HPC) drum of a gas turbine engine assembly will reduce the drum time constant, thereby reducing the re-slam characteristics of the drum causing a reduction in the cold build clearance (CBC), and hence the reduction in cruise clearance. A further reduction can be achieved by introducing radial inflow into the drum cavity to further increase the disc heat transfer coefficient in the cavity; hence a further reduction in disc drum time constant.

Thermo Fluid Dynamic Analysis of a Gas Turbine Transition-Piece

2014 ◽  
Author(s):  
Riccardo Da Soghe ◽  
Cosimo Bianchini ◽  
Antonio Andreini ◽  
Lorenzo Mazzei ◽  
Giovanni Riccio ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Gas Turbine ◽  
Fluid Dynamic ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Thermal Loads ◽  
Turbine Engine ◽  
Transition Piece

The transition-piece of a gas turbine engine is subjected to high thermal loads as it collects high temperature combustion products from the gas generator to a turbine. This generally produces high thermal stress levels in the casing of the transition piece, strongly limiting its life expectations and making it one of the most critical components of the entire engine. The reliable prediction of such thermal loads is hence a crucial aspect to increase the transition-piece life span and to assure safe operations. The present study aims to investigate the aero-thermal behaviour of a gas turbine engine transition-piece and in particular to evaluate working temperatures of the casing in relation to the flow and heat transfer situation inside and outside the transition-piece. Typical operating conditions are considered to determine the amount of heat transfer from the gas to the casing by means of CFD. Both conjugate approach and wall fixed temperature have been considered to compute the heat transfer coefficient, and more in general, the transition-piece thermal loads. Finally a discussion on the most convenient heat transfer coefficient expression is provided.

scholarly journals ОСОБЕННОСТИ ОБРАБОТКИ ЭКСПЕРИМЕНТАЛЬНЫХ ДАННЫХ ПРИ ОПРЕДЕЛЕНИИ КОЭФФИЦИЕНТА ТЕПЛООТДАЧИ В МАСЛЯНОЙ ПОЛОСТИ ОПОРЫ ГТД

2020 ◽  
pp. 73-81
Author(s):  
Илья Иванович Петухов ◽  
Тарас Петрович Михайленко ◽  
Андрей Александрович Брунак ◽  
Сергей Валерьевич Епифанов ◽  
Артём Викторович Ковалёв ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Turbine Engine ◽  
Temperature State ◽  
Wide Range ◽  
The Heat Transfer Coefficient

The development of gas turbine technology is accompanied by an increase in temperatures, pressures, and airflow velocity in the gas path. Increasing operating cycle parameters for gas turbine engine complicates the tasks of ensuring the permissible temperature state of engine parts, requires improving the methods of their calculation and design. This fact fully applies bearing assemblies, especially those operating in a hot environment, and causes interest in the study of thermohydraulic processes in the bearing chamber, which determines the temperature state of the rotor parts. The necessity of pressurizing the seals leads to the presence of the oil-air mixture in the bearing chamber. A wide range of operating parameters, flow inhomogeneity, phase disequilibrium, and phase separation significantly complicate the mathematical description of processes in the bearing chamber, including the use of CFD-modeling. Therefore, considerable attention is paid to experimental research. The experimental results are used not only to verify mathematical models but also to obtain generalizing dependencies. Most often, the desired value is the heat transfer coefficient in the oil cavity of the support. The article deals with the heat transfer features in the near-wall zone of the gas-turbine engine bearing chamber which were associated with the presence of oil-air flow. Also, approaches to the experimental determination of the heat transfer coefficient were analyzed and an appropriate system for measuring the local temperatures of the media was formed. The values of the error of the experimental heat transfer coefficient and the degree of influence of the determining factors were estimated. The contribution of the non-uniformity of the temperature field in the walls of the chamber and the uncertainty in the value of the temperature of the flow core was determined. The advantages of using the averaged heat transfer coefficient for engineering calculations and the significant influence of the averaging method on its value were also shown. Averaging over the heat flux density corresponds most accurately to the tasks of such calculations, at which the total heat flux through the chamber walls does not change.

scholarly journals CHARACTERISTICS OF HEAT TRANSFER IN FIRE TUBE OF MARINE GAS TURBINE ENGINE IN STARTING MODE

2018 ◽  
pp. 66-74
Author(s):  
Yuri Gorjanovich Volodin ◽  
Yury Ivanovich Matveev ◽  
Mikhail Yurievich Khramov
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Heat Flow ◽  
Turbulent Boundary Layer ◽  
Gas Turbine ◽  
Gas Flow ◽  
Experimental Studies ◽  
Gas Turbine Engine ◽  
Working Fluid ◽  
Turbine Engine

The paper presents the results of experimental studies of heat transfer in a cylindrical tube, which is a simulation model of a fire tube. The experiments were performed on a gas-dynamic pipe of open type. The starting mode during operation of the gas turbine engine is one of the main modes in which failures sometimes occur. The failure may occur due to external heat transfer mode, when the thermal parameters of the gas flow exceed the calculated values and there takes place intense local heating of the streamlined surface of the structural element(s) of the engine. Experimental studies were carried out at different intensity of the increasing temperature of the working fluid, which allowed to fix the phenomenon of laminarization of the thermal turbulent boundary layer at the heat flow directed from the gas flow to the channel wall. In the event of laminarization phenomenon, the values of local heat transfer coefficients are reduced by 2.5-3 times. Since the discovery of this phenomenon, it has also been observed in various situations of accelerating the gas flow and even at high degrees of heating of the cylindrical pipe wall under stationary flow conditions. This phenomenon has been recorded for the first time in the non-stationary mode and the specified direction of the heat flow. The temperature head or temperature factor is proposed as a laminarization parameter of a turbulent boundary layer, and the boundary of the laminarization area of a turbulent boundary layer is Δ T ≥ 700 K.

The Influence of Humidity on the Creep Life of a High Pressure Gas Turbine Blade: Part II—Case Study

2012 ◽  
Author(s):  
S. Eshati ◽  
P. Laskaridis ◽  
A. Haslam ◽  
P. Pilidis
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Life Assessment ◽  
Coolant Temperature ◽  
Creep Life

The determination of the rate of heat transfer from the turbine blade in a cross flow is important in hot section gas turbine life assessment. For design purposes, the rate of heat transfer is normally fixed by semi-empirical correlations. These correlations require knowledge of fluid properties which depend on temperature. For gases these properties are normally available only for the dry state, thus the possible effect of the water vapour content has been overlooked. Many gas turbines operate in environments in which air humidity is very low and therefore has little influence on gas turbine performance. However humidity becomes more important in hot, humid climates where there are large variations in ambient absolute humidity, especially in hot and humid climates. The aim of this paper is to investigate and present the effect of humidity at different operating conditions on the turbine blade coolant heat transfer and blade creep life. The effect of humidity was considered only on the air coolant side. he The heat transfer coefficient on the hot side was calculated for dry hot gas. This avoided the balancing effect of each other (heat transfer coefficient coolant side and hot side). The WAR at each operating point is quantified based on the ambient temperature and the relative humidity (0%–100%). Results showed that with increasing WAR the blade inlet coolant temperature reduced along the blade span. The blade metal temperature at each section was reduced as WAR increased, which in turn increased the blade creep life. The increase in WAR increased the specific heat of the coolant and increased the heat transfer capacity of the coolant air flow. Different operating points were also evaluated at different WAR and Tamb to identify the effect of WAR on the creep life. The results showed that an increase in WAR increased the blade creep life. The creep life of the blade at each section of interest was obtained as a function of the blade section stress and the blade metal section temperature using the LMP approach.

scholarly journals Gas Turbine Main Shaft Internal Flow and Heat Transfer

1991 ◽  
Author(s):  
David V. Roscoe ◽  
Richard C. Buggeln ◽  
Peter M. Munsell ◽  
F. C. Hsing
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Gas Turbine ◽  
Wall Temperature ◽  
Internal Flow ◽  
Primary Objective ◽  
Turbine Engine ◽  
Cooling Flow ◽  
Low Pressure Turbine

A CFD analysis of the cooling flow through a gas turbine engine low pressure turbine shaft is presented. Three cases are considered in which throughflow and rotation rate are varied. The primary objective of the analysis was to derive improved heat transfer coefficient information, over those obtainable via semi-empirical means. The coefficients so obtained were then used in a one-dimensional, time-dependent analysis for use in predicting shaft wall temperature throughout a snap acceleration phase of the engine. A second objective was to obtain insight into the flow structure within the shaft with a view to possible design input in future engine programs. Results presented include detailed velocity vector plots at select locations, heat transfer coefficient distributions for each case and finally, for Case 2 predicted wall temperature vs. time is shown in conjunction with engine test data.

Thermofluid Dynamic Analysis of a Gas Turbine Transition-Piece

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Riccardo Da Soghe ◽  
Cosimo Bianchini ◽  
Antonio Andreini ◽  
Lorenzo Mazzei ◽  
Giovanni Riccio ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Combustion Products ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Thermal Loads ◽  
Gas Generator ◽  
Fixed Temperature ◽  
Turbine Engine ◽  
Transition Piece

The transition-piece of a gas turbine engine is subjected to high thermal loads as it collects high temperature combustion products from the gas generator to a turbine. This generally produces high thermal stress levels in the casing of the transition piece, strongly limiting its life expectations and making it one of the most critical components of the entire engine. The reliable prediction of such thermal loads is hence a crucial aspect to increase the transition-piece life span and to assure safe operations. The present study aims to investigate the aerothermal behavior of a gas turbine engine transition-piece and in particular to evaluate working temperatures of the casing in relation to the flow and heat transfer situation inside and outside the transition-piece. Typical operating conditions are considered to determine the amount of heat transfer from the gas to the casing by means of computational fluid dynamics (CFD). Both conjugate approach and wall fixed temperature have been considered to compute the heat transfer coefficient (HTC), and more in general, the transition-piece thermal loads. Finally a discussion on the most convenient HTC expression is provided.

scholarly journals Heat Transfer and Flow on the Squealer Tip of a Gas Turbine Blade

2000 ◽  
Author(s):  
Gm S. Azad ◽  
Je-Chin Han ◽  
Robert J. Boyle
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Gas Turbine ◽  
Rotor Blade ◽  
Static Pressure ◽  
Cavity Surface ◽  
Edge Region ◽  
Blade Tip ◽  
The Heat Transfer Coefficient

Experimental investigations are performed to measure the detailed heat transfer coefficient and static pressure distributions on the squealer tip of a gas turbine blade in a five-bladed stationary linear cascade. The blade is a 2-dimensional model of a modern first stage gas turbine rotor blade with a blade tip profile of a GE-E3 aircraft gas turbine engine rotor blade. A squealer (recessed) tip with a 3.77% recess is considered here. The data on the squealer tip are also compared with a flat tip case. All measurements are made at three different tip gap clearances of about 1%, 1.5%, and 2.5% of the blade span. Two different turbulence intensities of 6.1% and 9.7% at the cascade inlet are also considered for heat transfer measurements. Static pressure measurements are made in the mid-span and near-tip regions, as well as on the shroud surface opposite to the blade tip surface. The flow condition in the test cascade corresponds to an overall pressure ratio of 1.32 and an exit Reynolds number based on the axial chord of 1.1×106. A transient liquid crystal technique is used to measure the heat transfer coefficients. Results show that the heat transfer coefficient on the cavity surface and rim increases with an increase in tip clearance. The heat transfer coefficient on the rim is higher than the cavity surface. The cavity surface has a higher heat transfer coefficient near the leading edge region than the trailing edge region. The heat transfer coefficient on the pressure side rim and trailing edge region is higher at a higher turbulence intensity level of 9.7% over 6.1% case. However, no significant difference in local heat transfer coefficient is observed inside the cavity and the suction side rim for the two turbulence intensities. The squealer tip blade provides a lower overall heat transfer coefficient when compared to the flat tip blade.

Sign in / Sign up

Export Citation Format

Share Document