Experimental Study on Pressure Losses in Porous Materials

2018 ◽  
Author(s):  
Giacomo Fantozzi ◽  
Mats Kinell ◽  
Sara Rabal Carrera ◽  
Jenny Nilsson ◽  
Yves Kuesters
Keyword(s):  
Discharge Coefficient ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Turbine Engine ◽  
Geometrical Properties ◽  
Pressure Losses ◽  
Technological Advances ◽  
Pore Radius Distribution ◽  
Engine Components ◽  
Test Objects

Recent technological advances in the field of additive manufacturing have made possible to manufacture turbine engine components characterized by controlled permeability in desired areas. These have shown great potential in cooling application such as convective cooling and transpiration cooling and may in the future contribute to an increase of the turbine inlet temperature. This study investigates the effects of the pressure ratio, the thickness of the porous material and the hatch distance used during manufacturing on the discharge coefficient. Moreover, two different porous structures were tested and in total 70 test objects were investigated. Using a scanning electron microscope, it is shown that the porosity and pore radius distribution, which are a result from the used laser power, laser speed and hatch distance during manufacturing, will characterize the pressure losses in the porous sample. Furthermore, the discharge coefficient increases with increasing pressure ratio, while it decreases with increasing thickness to diameter ratio. The obtained experimental data was used to develop a correlation for the discharge coefficient as a function of the geometrical properties and the pressure ratio.

Experimental Study on Pressure Losses in Porous Materials

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Giacomo Fantozzi ◽  
Mats Kinell ◽  
Sara Rabal Carrera ◽  
Jenny Nilsson ◽  
Yves Kuesters
Keyword(s):  
Discharge Coefficient ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Turbine Engine ◽  
Geometrical Properties ◽  
Pressure Losses ◽  
Technological Advances ◽  
Pore Radius Distribution ◽  
Engine Components ◽  
Test Objects

Recent technological advances in the field of additive manufacturing have made possible to manufacture turbine engine components characterized by controlled permeability in desired areas. These have shown great potential in cooling application such as convective cooling and transpiration cooling and may in the future contribute to an increase of the turbine inlet temperature. This study investigates the effects of the pressure ratio, the thickness of the porous material, and the hatch distance used during manufacturing on the discharge coefficient. Moreover, two different porous structures were tested, and in total, 70 test objects were investigated. Using a scanning electron microscope, it is shown that the porosity and pore radius distribution, which are a result from the used laser power, laser speed, and hatch distance during manufacturing, will characterize the pressure losses in the porous sample. Furthermore, the discharge coefficient increases with increasing pressure ratio, while it decreases with increasing thickness to diameter ratio. The obtained experimental data were used to develop a correlation for the discharge coefficient as a function of the geometrical properties and the pressure ratio.

Experimental Study on Pressure Losses in Circular Orifices With Inlet Cross Flow

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Daniel Feseker ◽  
Mats Kinell ◽  
Matthias Neef
Keyword(s):  
Experimental Study ◽  
Film Cooling ◽  
Gas Turbines ◽  
Discharge Coefficient ◽  
Pressure Ratio ◽  
Cross Flow ◽  
Pressure Losses ◽  
Wide Range ◽  
Cooling Hole ◽  
Secondary Air

The ability to understand and predict the pressure losses of orifices is important in order to improve the air flow within the secondary air system. This experimental study investigates the behavior of the discharge coefficient for circular orifices with inlet cross flow which is a common flow case in gas turbines. Examples of this are at the inlet of a film cooling hole or the feeding of air to a blade through an orifice in a rotor disk. Measurements were conducted for a total number of 38 orifices, covering a wide range of length-to-diameter ratios, including short and long orifices with varying inlet geometries. Up to five different chamfer-to-diameter and radius-to-diameter ratios were tested per orifice length. Furthermore, the static pressure ratio across the orifice was varied between 1.05 and 1.6 for all examined orifices. The results of this comprehensive investigation demonstrate the beneficial influence of rounded inlet geometries and the ability to decrease pressure losses, which is especially true for higher cross flow ratios where the reduction of the pressure loss in comparison to sharp-edged holes can be as high as 54%. With some exceptions, the chamfered orifices show a similar behavior as the rounded ones but with generally lower discharge coefficients. Nevertheless, a chamfered inlet yields lower pressure losses than a sharp-edged inlet. The obtained experimental data were used to develop two correlations for the discharge coefficient as a function of geometrical as well as flow properties.

Status of the Automotive Ceramic Gas Turbine Development Progrem: Year Four Progress

1995 ◽  
Author(s):  
Tsubura Nishiyama ◽  
Masumi Iwai ◽  
Norio Nakazawa ◽  
Masafumi Sasaki ◽  
Haruo Katagiri ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Inlet Temperature ◽  
Rotor Speed ◽  
Turbine Inlet Temperature ◽  
Turbine Engine ◽  
Turbine Inlet ◽  
Basic Engine ◽  
Energy Center ◽  
Engine Components

The seven-year program, designated “Research & Development of Automotive Ceramic Gas Turbine Engine (CGT Program)”, was started in 1990 with the object of demonstrating the advantageous potentials of ceramic gas turbines for automotive use. This CGT Program is conducted by Petroleum Energy Center. The basic engine is a 100kW, single-shaft regenerative engine having turbine inlet temperature of 1350°C and rotor speed of 110000rpm. In the forth year of the program, the engine components were experimentally evaluated and improved in the various test rigs, and the first assembly test including rotating and stationary components, was performed this year under the condition of turbine inlet temperature of 1200°C.

Status of the Automotive Ceramic Gas Turbine Development Program

1993 ◽  
Vol 115 (1) ◽  
pp. 42-50 ◽  
Author(s):  
T. Itoh ◽  
H. Kimura
Keyword(s):  
Gas Turbine ◽  
Development Program ◽  
First Year ◽  
Inlet Temperature ◽  
Stage Design ◽  
Turbine Engine ◽  
Program Schedule ◽  
Basic Engine ◽  
Monolithic Ceramics ◽  
Engine Components

A seven-year program, designated “Research and Development of Automotive CGT,” commenced in June 1990 with the object of demonstrating the potential advantages of ceramic gas turbine engines for automotive use. This program has been conducted by the Petroleum Energy Center (PEC) with the support of the Ministry of International Trade and Industry. The engine demonstration project in this program is being handled by a team from Japan Automobile Research Institute, Inc. (JARI). This paper describes the activities of the first year of the seven-year program, and includes the project goals and objectives, the program schedule, and the first-stage design of an experimental automotive ceramic gas turbine (CGT) engine and its components. The basic engine is a 100 kW, single-shaft gas turbine engine having a turbine inlet temperature of 1350°C and a rotor speed of 110,000 rpm. The primary engine components including the turbine hot flow path components have been designed using monolithic ceramics and are scheduled to be produced during the second year of the program.

Surge-Induced Structural Loads in Gas Turbines

1980 ◽  
Vol 102 (1) ◽  
pp. 162-168 ◽  
Author(s):  
R. S. Mazzawy
Keyword(s):  
Gas Turbines ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Turbine Engine ◽  
Compression System ◽  
Engine Design ◽  
Steady State Levels ◽  
Flow Compression ◽  
Engine Components ◽  
Bypass Ratio

The axial flow compression system of a modern gas turbine engine normally delivers a large quantity of airflow at relatively high velocity. The sudden stoppage (and reversal) of this flow when an engine surges can result in structural loads in excess of steady state levels. These loads can be quite complex due to inherent asymmetry in the surge event. The increasing requirements for lighter weight engine structures, coupled with the higher pressure ratio cycles required for minimizing fuel consumption, make the accurate prediction of these loads an important part of the engine design process. This paper is aimed toward explaining the fluid mechanics of the surge phenomenon and its impact on engine structures. It offers relatively simple models for estimating surge-induced loads on various engine components. The basis for these models is an empirical correlation of surge-induced inlet overpressure based on engine pressure ratio and bypass ratio. An approximate estimate of the post-surge axial pressure distribution can be derived from this correlation by assuming that surge initiation occurs in the rear of the compression system.

scholarly journals Technical Approach for a MultiPurpose Small Power Unit

1988 ◽  
Author(s):  
Robert G. Thompson ◽  
Sidney D. Parker
Keyword(s):  
Gas Turbine ◽  
Power Unit ◽  
Pressure Ratio ◽  
Technical Approach ◽  
Program Goal ◽  
Small Power ◽  
Turbine Engine ◽  
Component Efficiency ◽  
And Performance ◽  
Engine Components

This paper describes the technical approach used to select the engine configuration and performance cycle for a small gas turbine engine. The work was done during the preparation of a proposal to the U.S. Army for an advanced gas-turbine-based MultiPurpose Small Power Unit (MPSPU) in the 50–75 SHP class. Uprating to 100 hp (74.6 kw) with the fewest possible component changes was also desired and will be demonstrated. The proposal was successful, and the resultant engine offering, the T-100 MPSPU, is currently under development. The performance analyses used to quantify the T-100 MPSPU cycle were unique in that component efficiency correlations were used interactively when estimating performance at high levels of work (or pressure ratio per stage) with relatively small size components. The MPSPU program goal is to verify gas turbine technology advancements in small engine components, materials and design techniques that will lead to significant reductions in fuel consumption for this size class engine. Successful incorporation of these technologies will lead to significant savings in fuel usage and logistic requirements.

scholarly journals Development of the AGT101 Regenerator Seals

1987 ◽  
Author(s):  
C. A. Fucinari ◽  
J. K. Vallance ◽  
C. J. Rahnke
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Dynamic Test ◽  
Development Program ◽  
Analytical Techniques ◽  
Gas Turbine Engine ◽  
Inlet Temperature ◽  
Gas Temperature ◽  
Turbine Engine ◽  
Seal Design

The design and development of the regenerator seals used in the AGT101 gas turbine engine are described in this paper. The all ceramic AGT101 gas turbine engine was designed for 100 hp at 5:1 pressure ratio with 2500F (1371C) turbine inlet temperature. Six distinct phases of seal design were investigated experimentally and analytically to develop the final design. Static and dynamic test rig results obtained during the seal development program are presented. In addition, analytical techniques are described. The program objectives of reduced seal leakage, without additional diaphragm cooling, to 3.6% of total engine airflow and higher seal operating temperature resulting from the 2000F (1093C) inlet exhaust gas temperature were met.

Performance Analysis of a 50KW Turbogenerator Gas Turbine Engine

1998 ◽  
Author(s):  
S. Y. Kim ◽  
M. R. Park ◽  
S. Y. Cho
Keyword(s):  
Performance Analysis ◽  
Gas Turbine ◽  
Pressure Ratio ◽  
Hybrid Vehicle ◽  
Gas Turbine Engine ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Turbine Engine ◽  
Design Point ◽  
Turbine Inlet

This paper describes on/off design performance of a 50KW turbogenerator gas turbine engine for hybrid vehicle application. For optimum design point selection, a relevant pa4rameter study is carried out. The turbogenerator gas turbine engine for a hybrid vehicle is expected to be designed for maximum fuel economy, ultra low emissions, and very low cost. A compressor, combustor, turbine, and a permanent-magnet generator will be mounted on a single high speed (80,000 rpm) shaft that will be supported on air bearings. As the generator is built into the shaft, gearbox and other moving parts become unnecessary and thus will increase the system’s reliability and reduce the manufacturing cost. The engine has a radial compressor and turbine with design point pressure ratio of 4.0. This pressure ratio was set based on calculation of specific fuel consumption and specific power variation with pressure ratio. For the turbine inlet temperature, a rather conservative value of 1100K was selected. Designed mass flow rate was 0.5 kg/sec. Parametric study of the cycle indicates that specific work and efficiency increase at a given pressure ratio and turbine inlet temperature. Off design analysis shows that the gas turbine system reaches self operating condition at about N/NDP = 0.48. Bleeding air for a turbine stator cooling is omitted considering the low TIT in the present engine and to enable the simple geometric configuration for manufacturing purpose. Various engine performance simulations including ambient temperature influence, surging at part load condition; transient analysis were performed to secure the optimum engine operating characteristics. Surge margin throughout the performance analysis were maintained to be over 50% approximately. Present analysis will be compared with performance test result which is scheduled at the end of 1998.

The Application of Ceramics to the Small Gas Turbine

1970 ◽  
Author(s):  
A. F. McLean
Keyword(s):  
Gas Turbine ◽  
Lower Cost ◽  
Ceramic Materials ◽  
Turbine Engines ◽  
Inlet Temperature ◽  
Gas Turbine Engines ◽  
Turbine Inlet Temperature ◽  
Turbine Engine ◽  
Engine Components ◽  
Processing Techniques

This paper reviews the limitations today’s superalloys exercise on the realization of the potential of the gas turbine engine. Ceramic materials are suggested as a means of achieving lower cost and higher turbine inlet temperature in small gas turbine engines. The paper serves to introduce ceramic materials and processing techniques and identifies silicon nitride, silicon carbide and lithium-alumina-silicate as promising materials for high temperature turbine engine components.

Advances in the Development of a Micro-Gas Turbine Engine at Onera

2013 ◽  
Author(s):  
O. Dessornes ◽  
S. Landais ◽  
R. Valle ◽  
A. Fourmaux ◽  
S. Burguburu ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Gas Turbine Engine ◽  
Inlet Temperature ◽  
Portable Devices ◽  
Good Efficiency ◽  
Turbine Engine ◽  
Micro Gas Turbine ◽  
Overall Efficiency

To reduce the size and weight of power generation machines for portable devices, several systems to replace the currently used heavy batteries are being investigated worldwide. As micro gas turbines are expected to offer the highest power density, several research groups launched programs to develop ultra micro gas turbines: IHI firm (Japan), PowerMEMS Consortium (Belgium). At Onera, a research program called DecaWatt is under development in order to realize a demonstrator of a micro gas turbine engine in the 50 to 100 Watts electrical power range. A single-stage gas turbine is currently being studied. First of all, a calculation of the overall efficiency of the micro gas turbine engine has been carried out according to the pressure ratio, the turbine inlet temperature and the compressor and turbine efficiencies. With realistic hypotheses, we could obtain an overall efficiency of about 5% to 10% which leads to around 200 W/kg when taking into account the mass of the micro gas turbine engine, its electronics, fuel and packaging. Moreover, the specific energy could be in the range 300 to 600 Wh/kg which exceeds largely the performance of secondary batteries. To develop such a micro gas turbine engine, experimental and computational work focused on: • a 10 mm in diameter centrifugal compressor, with the objective to obtain a pressure ratio of about 2.5 • a radial inflow turbine • journal and thrust gas bearings (lobe bearings and spiral grooves) and their manufacturing • a small combustor working with hydrogen or hydrocarbon gaseous fuel (propane) • a high rotation speed micro-generator • the choice of materials Components of this tiny engine were tested prior to the test with all the parts assembled together. Tests of the generator at 700,000 rpm showed a very good efficiency of this component. In the same way, compressor testing has been performed up to 500,000 rpm and has shown that the nominal compression rate at the 840,000 rpm nominal speed should be nearly reached.

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