scholarly journals Thermal Characteristics Study of the Bump Foil Thrust Gas Bearing

2021 ◽  
Vol 11 (9) ◽  
pp. 4311
Author(s):  
Xiaomin Liu ◽  
Changlin Li ◽  
Jianjun Du ◽  
Guodong Nan
Keyword(s):  
Gas Flow ◽  
Three Dimensional ◽  
Thermal Characteristics ◽  
Rotor Speed ◽  
External Cooling ◽  
Deformation Equation ◽  
Simulation And Experiment ◽  
Cooling Air Flow ◽  
Cooling Air ◽  
Gas Bearing

In this paper, a thermo-hydrodynamic model of the bump foil thrust gas bearing is developed, which solves the coupled gas film three-dimensional energy equation, non-isothermal Reynolds equation, and the foil deformation equation. The effects of bearing speed, thrust load, and external cooling gas on the bearing temperature field are calculated and analyzed. The test rig of foil thrust gas bearing was built to measure the bearing temperature under different working conditions. Both simulation and experiment results show that there exist temperature gradients on the top foil both in the circumferential and radial directions. The simulation results also shows that the top foil side of the gas film has the highest temperature value in the entire lubrication field, and the position of highest temperature moves radially inward on the thrust plate side as the rotor speed increases. The gas film temperature increases with the increasing rotor speed and bearing static load, and rotor speed has greater effects on the temperature variation. Cooling air flow passing through the bump foil is also considered in the simulations, and the cooling efficiency decreases as the mass of gas flow increases.

Modeling Contra-Rotating Turbomachinery Components for Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
A. Alexiou ◽  
I. Roumeliotis ◽  
N. Aretakis ◽  
A. Tsalavoutas ◽  
K. Mathioudakis
Keyword(s):  
Three Dimensional ◽  
Engine Performance ◽  
Performance Model ◽  
Speed Ratio ◽  
The Core ◽  
Fuel Burn ◽  
Core Concepts ◽  
Additional Table ◽  
Cooling Air Flow ◽  
Cooling Air

This paper presents a method of modeling contra-rotating turbomachinery components for engine performance simulations. The first step is to generate the performance characteristics of such components. In this study, suitably modified one-dimensional mean line codes are used. The characteristics are then converted to three-dimensional tables (maps). Compared to conventional turbomachinery component maps, the speed ratio between the two shafts is included as an additional map parameter and the torque ratio as an additional table. Dedicated component models are then developed that use these maps to simulate design and off-design operation at the component and engine levels. Using this approach, a performance model of a geared turbofan with a contra-rotating core (CRC) is created. This configuration was investigated in the context of the European program “NEW Aero-Engine Core Concepts” (NEWAC). The core consists of a seven-stage compressor and a two-stage turbine without interstage stators and with successive rotors running in the opposite direction through the introduction of a rotating outer spool. Such a configuration results in a reduced parts count, length, weight, and cost of the entire high pressure (HP) system. Additionally, the core efficiency is improved due to reduced cooling air flow requirements. The model is then coupled to an aircraft performance model and a typical mission is carried out. The results are compared against those of a similar configuration employing a conventional core and identical design point performance. For the given aircraft-mission combination and assuming a 10% engine weight saving when using the CRC arrangement over the conventional one, a total fuel burn reduction of 1.1% is predicted.

Modelling Contra-Rotating Turbomachinery Components for Engine Performance Simulations: The Geared Turbofan With Contra-Rotating Core Case

2012 ◽  
Author(s):  
A. Alexiou ◽  
I. Roumeliotis ◽  
N. Aretakis ◽  
A. Tsalavoutas ◽  
K. Mathioudakis
Keyword(s):  
Three Dimensional ◽  
Engine Performance ◽  
Performance Model ◽  
Speed Ratio ◽  
The Core ◽  
Fuel Burn ◽  
Core Concepts ◽  
Additional Table ◽  
Cooling Air Flow ◽  
Cooling Air

This paper presents a method of modelling contra-rotating turbomachinery components for engine performance simulations. The first step is to generate the performance characteristics of such components. In this study, suitably modified one-dimensional mean line codes are used. The characteristics are then converted to three-dimensional tables (maps). Compared to conventional turbomachinery component maps, the speed ratio between the two shafts is included as an additional map parameter and the torque ratio as an additional table. Dedicated component models are then developed that use these maps to simulate design and off-design operation at component and engine level. Using this approach, a performance model of a geared turbofan with a Contra-Rotating Core (CRC) is created. This configuration was investigated in the context of the European program NEWAC (NEW Aero-engine core Concepts). The core consists of a seven-stage compressor and a two-stage turbine without inter-stage stators and with successive rotors running in opposite direction through the introduction of a rotating outer spool. Such a configuration results in reduced parts count, length, weight and cost of the entire HP system. Additionally, the core efficiency is improved due to reduced cooling air flow requirements. The model is then coupled to an aircraft performance model and a typical mission is carried out. The results are compared against those of a similar configuration employing a conventional core and identical design point performance. For the given aircraft-mission combination and assuming a 10% engine weight saving when using the CRC arrangement over the conventional one, a total fuel burn reduction of 1.1% is predicted.

Thermal Conjugate Analysis of a First Stage Blade in a Gas Turbine

2000 ◽  
Author(s):  
Toshihiko Takahashi ◽  
Kazunori Watanabe ◽  
Takeshi Takahashi
Keyword(s):  
Heat Transfer ◽  
Numerical Method ◽  
Gas Turbine ◽  
Three Dimensional ◽  
Convection Heat Transfer ◽  
Surface Pattern ◽  
Accurate Estimation ◽  
Gas Temperature ◽  
Cooling Air Flow ◽  
Cooling Air

Three-dimensional numerical analyses of heat transfer were conducted by thermal conjugation of the inside and outside fields of a first stage rotor blade in a gas turbine, which consists of convection heat transfer and thermal conduction. The target of the analysis was a blade with multiple cooling holes. In order to make an accurate estimation of the blade temperature, the heat exchange in cooling passages, the outflow of cooling air and the effect of rotation were taken into account by the numerical method. The predicted distribution of surface temperature was in good agreement with the observed surface pattern on an actual blade. In addition case studies for bucket temperature were carried out using the present numerical method. It was shown that the temperature field inside the blade was severely influenced by the assumed distribution of inlet gas temperature and cooling air flow conditions. As a result, it is clear that the present analytical method is useful for prediction of blade temperature depending on various conditions in operation.

scholarly journals Off-Design Evaluation of a Multiple Expansion Reheating Gas Turbine in Cogeneration Applications

1991 ◽  
Author(s):  
Erio Benvenuti ◽  
Roberto Bettocchi ◽  
Giuseppe Cantore ◽  
Giorgio Negri Di Montenegro
Keyword(s):  
Gas Turbine ◽  
Air Flow ◽  
Thermal Power ◽  
Operational Flexibility ◽  
External Cooling ◽  
Heat Requirements ◽  
Cooling Air Flow ◽  
Performance Results ◽  
Air Control ◽  
Cooling Air

The multiple expansion reheating gas turbine proves to have a potential of good operational flexibility for the intrinsic capability of responding to variations in electric and thermal power demands without appreciable impact on efficiency. The present study deals with evaluation of the performance attainable in off-design operation, with power control obtained through changes in the first and second combustor firing temperatures and in the compressor intake air flow achieved by means of variable inlet guide vanes. Because of the important impact of the hot part cooling air flows on performance, the study includes also a hypothesis of controlling such flows in off-design operation through external means. The predicted off-design performance results superior in the hypothesis of external cooling air flow control, thus making such a system worthy of consideration for possible future developments of machines in this category. To evaluate the suitability of the multiple expansion reheating gas turbine in cogeneration applications, the electric efficiency and the electrical index have been taken into consideration. The capability of varying the reheating temperature represents an effective way of controlling the electrical index with good efficiencies in industrial cogeneration with strongly varying electric power and process heat requirements. With regard to the cooling air control through external means, implementation of such a more complex system seems to be avoidable at least when the gas turbine is intended specifically for application in cogeneration, because of its smaller impact on the overall efficiency of the system.

Development of Thermoelectric Conversion System for Waste Heat Recovery of Automobile Engine Exhaust Gas

2013 ◽  
Vol 284-287 ◽  
pp. 713-717 ◽  
Author(s):  
Tzer Ming Jeng ◽  
Sheng Chung Tzeng
Keyword(s):  
Thermoelectric Generator ◽  
Engine Speed ◽  
Waste Heat ◽  
Air Flow ◽  
Energy Output ◽  
Thermoelectric Conversion ◽  
External Cooling ◽  
Conversion System ◽  
Cooling Air Flow ◽  
Cooling Air

In the viewpoint of energy reutilization, this study combined high efficiency heat transfer with thermoelectric conversion technology to construct an efficiency testing platform for the waste heat recovering thermoelectric conversion system for real vehicles. A Toyota 2200c.c. vehicle with four-cylinder four-cycle engine was used for vehicle test to discuss the influence of the vehicle's engine speed and external cooling air flow on the energy output of the waste heat recovering thermoelectric conversion system. This study found that the energy output increases with the engine speed. However, if the engine speed is too high (exceeding 2500rpm), the thermoelectric generator can be overheated and damaged, which should be avoided. In addition, there is an optimal external cooling air flow generating the maximum energy output. The optimal external cooling air flow is 0.04 m3/sec in this study. At present, the 6 thermoelectric generator modules connected in series have the maximum electric power (P) output about 16W when the blowing air flow is 0.04 m3/sec and the engine speed is 2500 rpm.

TECHNICAL DEVELOPMENT OF HEAT ENERGY RECOVERY FOR VEHICLE POWER SYSTEM

2013 ◽  
Vol 37 (3) ◽  
pp. 885-894 ◽  
Author(s):  
Tzer-Ming Jeng ◽  
Sheng-Chung Tzeng
Keyword(s):  
Engine Speed ◽  
Waste Heat ◽  
Air Flow ◽  
Maximum Energy ◽  
Energy Output ◽  
External Cooling ◽  
Vehicle Test ◽  
Cooling Air Flow ◽  
Heat Energy Recovery ◽  
Cooling Air

A Toyota 2200 c.c. vehicle with four-cylinder four-cycle engine was used for real vehicle test to discuss the influence of the vehicle’s engine speed and external cooling air flow on the energy output of the waste heat recovering thermoelectric conversion system. This study found that the energy output increased with the engine speed. However, if the engine speed was too high (exceeding 2500 rpm), the thermoelectric generator would be overheated and damaged. Besides, there was an optimal external cooling air flow to generate the maximum energy output.

scholarly journals Cooling Characteristics of Film-Cooled Turbine Blades

1984 ◽  
Author(s):  
T. Abe ◽  
N. Doi ◽  
T. Kawaguchi ◽  
T. Yamane ◽  
T. Kumagai ◽  
...  
Keyword(s):  
Film Cooling ◽  
Small Deviation ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Cooling Effectiveness ◽  
Average Value ◽  
Pin Fin ◽  
Series Of Experiments ◽  
Cooling Air Flow ◽  
Cooling Air

A series of experiments was performed to measure the cooling effectiveness of pin-fin type blades applicable to the first-stage blades of the high pressure turbine for the Advanced Gas Turbine of Japan (AGTJ-100A). Actual pin-fin type blades were used in three-dimensional hot cascade tests. Resulting cooling effectiveness distributions in chordwise direction showed relatively small deviation from the high average value and closely corresponded with analytical predictions. Another major finding was that for film cooling blades, particularly with a shower head film cooling, it is essential in the cascade tests to set the ratio between the coolant and mainstream temperature at values the same as real conditions. This makes it possible to simulate cooling air flow distributions in the blades of high temperature actual turbines using low temperature tests. This is also applicable to vanes with a shower head film cooling.

Local Cooling Effectiveness Distribution of an Integrated Impingement and Pin Fin Cooling Configuration

2007 ◽  
Author(s):  
Chiyuki Nakamata ◽  
Fujio Mimura ◽  
Masahiro Matsushita ◽  
Takashi Yamane ◽  
Yoshitaka Fukuyama ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Gas Flow ◽  
Infrared Camera ◽  
Local Cooling ◽  
Cooling Effectiveness ◽  
Combustion Gas ◽  
Pin Fin ◽  
Test Pieces ◽  
Cooling Air Flow ◽  
Cooling Air

An integrated impingement and pin-fin cooling configuration is investigated experimentally. Temperature measurements have been performed for several test pieces with various pin/hole arrangements to clarify an influence of pin/hole arrangements on cooling effectiveness. The experiment has been conducted with 673K combustion gas flow and room temperature cooling air. Reynolds number of combustion gas flow is 380000 and Reynolds number of cooling air flow is in the range from 5000 to 30000. An infrared camera is used to measure a temperature distribution on a specimen surface. The area-averaged cooling effectiveness and the local cooling effectiveness are evaluated for each specimen and compared each other. There are evidences of the existence of pins on the local cooling effectiveness at the exact location of those. But the local cooling effectiveness are independent of the hole arrangement.

Real gas flow fields about three dimensional configurations

1983 ◽  
Author(s):  
A. BALAKRISHNAN ◽  
C. LOMBARD ◽  
W.C. DAVY
Keyword(s):  
Gas Flow ◽  
Three Dimensional ◽  
Flow Fields ◽  
Real Gas

scholarly journals Modeling of three-dimensional exciplex pumped fluid Cs vapor laser with transverse and longitudinal gas flow

2021 ◽  
Vol 9 ◽  
Author(s):  
Chenyi Su ◽  
Xingqi Xu ◽  
Jinghua Huang ◽  
Bailiang Pan
Keyword(s):  
Wall Temperature ◽  
Laser Power ◽  
Gas Flow ◽  
Particle Density ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Heat Accumulation ◽  
Vapor Laser ◽  
Output Laser Power ◽  
Output Laser

Abstract Considering the thermodynamical fluid mechanics in the gain medium and laser kinetic processes, a three-dimensional theoretical model of an exciplex-pumped Cs vapor laser with longitudinal and transverse gas flow is established. The slope efficiency of laser calculated by the model shows good agreement with the experimental data. The comprehensive three-dimensional distribution of temperature and particle density of Cs is depicted. The influence of pump intensity, wall temperature, and fluid velocity on the laser output performance is also simulated and analyzed in detail, suggesting that a higher wall temperature can guarantee a higher output laser power while causing a more significant heat accumulation in the cell. Compared with longitudinal gas flow, the transverse flow can improve the output laser power by effectively removing the generated heat accumulation and alleviating the temperature gradient in the cell.

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