Redesigning the Auxiliary Power Unit Bleed Air Venturi

2012 ◽  
Author(s):  
Adam Dick ◽  
Peter Diamond
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Power Unit ◽  
Mass Flow ◽  
Flow Rate ◽  
Cold Weather ◽  
Auxiliary Power Unit ◽  
Auxiliary Power ◽  
Main Engine ◽  
Cooling Air

This paper examines the analysis of re-designing the Auxiliary Power Unit (APU) bleed air spool piece used on the Landing Craft, Air Cushion (LCAC). The APU supplies bleed air for main engine (ME) starting, anti-icing of the propeller shrouds during cold weather conditions and anti-icing of the filtration system that supplies both ME compartment cooling air and the APU gas turbine combustion air. An air-blast cockpit windshield cleaning system is also powered by APU bleed air. A spool piece is a venturi whose function is to limit a specific amount of airflow as it passes through a system. The current spool piece venturi dimensions allow an excess in APU bleed air to on-craft components, resulting in an exhaust gas temperature (EGT) over-temp in the gas turbine power producer. Such operating conditions occur during cold weather testing, when port and starboard propeller shroud anti-ice systems and APU combustion air/main engine compartment cooling air anti-ice systems are operating. In order to rectify this issue, a model analysis was created, determining the proper dimension of the spool piece venturi. Because spool piece venturies have been implemented fleet wide, it was a priority to reduce fabrication expenses of new materials. To best achieve this, the analysis will determine the size of a plain venturi that can be installed within the existing spool pieces. Referring to engine specifications, APU bleed air was limited to a certain flow rate. However, anti-ice components also required a specific mass flow rate in order to operate properly. It is within these boundaries that the proper diameter of the venturi was determined. This issue further expands upon the analysis of thermal testing, inlet and outlet pressures and the mass flow rate of the new venturi dimension.

scholarly journals Gemini T-20G-8 XM1 Tank APU

1981 ◽  
Author(s):  
C. Rodgers ◽  
J. Zeno ◽  
E. A. Drury ◽  
A. Karchon
Keyword(s):  
Gas Turbine ◽  
Power Unit ◽  
Weather Conditions ◽  
Cold Weather ◽  
Turbine Engine ◽  
Auxiliary Power Unit ◽  
Auxiliary Power ◽  
Generator Sets ◽  
Main Engine ◽  
The U.S

Auxiliary power is often provided on combat vehicles in the U.S. Army for battery charging, operation of auxiliary vehicle equipment when the main engine is not running, or to provide assistance in starting the main engine in extreme cold weather conditions. The use of a gas turbine for these applications is particularly attractive, due to its small size and lightweight. In November 1978, the U.S. Army Tank-Automotive Research and Development Command, Warren, MI awarded a contract to the Turbomach Division of Solar Turbines International, San Diego, CA, for the development of a 10 kW 28 vdc gas turbine powered auxiliary power unit (APU) for installation in the XM1 main battle tank. This paper describes the general features of the Solar Turbomach T-20G-8 Auxiliary Power Unit, a single-shaft gas turbine driven generator set which has been developed under this contract. This APU is one of the family of Gemini powered APUs and is a derivative of the U.S. Army 10 kW gas turbine engine-driven, 60 and 400 Hz generator sets developed by Solar. The electrical components were newly developed for this particular application. Currently, the APU is in qualification testing both in the laboratory and in the XM1 main battle tank.

Effect of pre-swirl nozzle closure modes on unsteady flow and heat transfer characteristics in a pre-swirl system of aero-engine

2021 ◽  
pp. 095441002110191
Author(s):  
Gaowen Liu ◽  
Zhao Lei ◽  
Aqiang Lin ◽  
Qing Feng ◽  
Yan Chen
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Temperature Drop ◽  
Thermodynamic Characteristics ◽  
Circumferential Direction ◽  
Temperature Changes ◽  
Air Supply ◽  
Cooling Air

The pre-swirl system is of great importance for temperature drop and cooling air supply. This study aims to investigate the influencing mechanism of heat transfer, nonuniform thermodynamic characteristics, and cooling air supply sensitivity in a pre-swirl system by the application of the flow control method of the pre-swirl nozzle. A novel test rig was proposed to actively control the supplied cooling air mass flow rate by three adjustable pre-swirl nozzles. Then, the transient problem of the pre-swirl system was numerically conducted by comparison with 60°, 120°, and 180° rotating disk cavity cases, which were verified with the experiment results. Results show that the partial nozzle closure will aggravate the fluctuation of air supply mass flow rate and temperature. When three parts of nozzles are closed evenly at 120° in the circumferential direction, the maximum value of the nonuniformity coefficient of air supply mass flow rate changes to 3.1% and that of temperature changes to 0.25%. When six parts of nozzles are closed evenly at 60° in the circumferential direction, the maximum nonuniformity coefficient of air supply mass flow rate changes to 1.4% and that of temperature changes to 0.20%. However, different partial nozzle closure modes have little effect on the average air supply parameters. Closing 14.3% of the nozzle area will reduce the air supply mass flow rate by 9.9% and the average air supply temperature by about 1 K.

Low-Emissions Technology Development for Auxiliary Power Unit Combustion Systems

2021 ◽  
Author(s):  
Thomas Bronson ◽  
Rudy Dudebout ◽  
Nagaraja Rudrapatna
Keyword(s):  
Gas Turbine ◽  
Power Unit ◽  
Fuel Injection ◽  
Oxides Of Nitrogen ◽  
Combustion System ◽  
Auxiliary Power Unit ◽  
Criteria Pollutants ◽  
Auxiliary Power ◽  
Combustion Systems ◽  
Aircraft Application

Abstract The aircraft Auxiliary Power Unit (APU) is required to provide power to start the main engines, conditioned air and power when there are no facilities available and, most importantly, emergency power during flight operation. Given the primary purpose of providing backup power, APUs have historically been designed to be extremely reliable while minimizing weight and fabrication cost. Since APUs are operated at airports especially during taxi operations, the emissions from the APUs contribute to local air quality. There is clearly significant regulatory and public interest in reducing emissions from all sources at airports, including from APUs. As such, there is a need to develop technologies that reduce criteria pollutants, namely oxides of nitrogen (NOx), unburned hydrocarbons (UHC), carbon monoxide (CO) and smoke (SN) from aircraft APUs. Honeywell has developed a Low-Emissions (Low-E) combustion system technology for the 131-9 and HGT750 family of APUs to provide significant reduction in pollutants for narrow-body aircraft application. This article focuses on the combustor technology and processes that have been successfully utilized in this endeavor, with an emphasis on abating NOx. This paper describes the 131-9/HGT750 APU, the requirements and challenges for small gas turbine engines, and the selected strategy of Rich-Quench-Lean (RQL) combustion. Analytical and experimental results are presented for the current generation of APU combustion systems as well as the Low-E system. The implementation of RQL aerodynamics is well understood within the aero-gas turbine engine industry, but the application of RQL technology in a configuration with tangential liquid fuel injection which is also required to meet altitude ignition at 41,000 ft is the novelty of this development. The Low-E combustion system has demonstrated more than 25% reduction in NOx (dependent on the cycle of operation) vs. the conventional 131-9 combustion system while meeting significant margins in other criteria pollutants. In addition, the Low-E combustion system achieved these successes as a “drop-in” configuration within the existing envelope, and without significantly impacting combustor/turbine durability, combustor pressure drop, or lean stability.

Effect of Active Modulation of Through-Casing Coolant Injection on Turbine Efficiency

2017 ◽  
Author(s):  
Brian M. T. Tang ◽  
Marko Bacic ◽  
Peter T. Ireland
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Total Pressure ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Turbine Efficiency ◽  
Coolant Injection ◽  
Cooling Air

This paper presents a computational investigation into the impact of cooling air injected through the stationary over-tip turbine casing on overall turbine efficiency. The high work axial flow turbine is representative of the high pressure turbine of a civil aviation turbofan engine. The effect of active modulation of the cooling air is assessed, as well as that of the injection locations. The influence of the through-casing coolant injection on the turbine blade over-tip leakage flow and the associated secondary flow features are examined. Transient (unsteady) sliding mesh simulations of a one turbine stage rotor-stator domain are performed using periodic boundary conditions. Cooling air configurations with a constant total pressure air supply, constant mass flow rate and actively controlled total pressure supply are assessed for a single geometric arrangement of cooling holes. The effects of both the mass flow rate of cooling air and the location of its injection relative to the turbine rotor blade are examined. The results show that all of the assessed cooling configurations provided a benefit to turbine row efficiency of between 0.2 and 0.4 percentage points. The passive and constant mass flow rate configurations reduced the over-tip leakage flow, but did so in an inefficient manner, with decreasing efficiency observed with increasing injection mass flow rate beyond 0.6% of the mainstream flow, despite the over-tip leakage mass flow rate continuing to reduce. By contrast, the active total pressure controlled injection provided a more efficient manner of controlling this leakage flow, as it permitted a redistribution of cooling air, allowing it to be applied in the regions close to the suction side of the blade tip which more directly reduced over-tip leakage flow rates and hence improved efficiency. Cooling air injected close to the pressure side of the rotor blade was less effective at controlling the leakage flow, and was associated with increased aerodynamic loss in the passage vortex.

Fiber Metal Acoustic Material for Gas Turbine Exhaust Environments

1989 ◽  
Vol 111 (1) ◽  
pp. 181-185
Author(s):  
M. S. Beaton
Keyword(s):  
Gas Turbine ◽  
Power Unit ◽  
Broad Band ◽  
Acoustic Energy ◽  
Acoustic Properties ◽  
Roll Forming ◽  
Sound Waves ◽  
Auxiliary Power Unit ◽  
Auxiliary Power ◽  
Fiber Metal

FELTMETAL® fiber metal acoustic materials function as broad band acoustic absorbers. Their acoustic energy absorbance occurs through viscous flow losses as sound waves pass through the tortuous pore structure of the material. A new FELTMETAL® fiber metal acoustic material has been designed for use in gas turbine auxiliary power unit exhaust environments without supplemental cooling. The physical and acoustic properties of FM 827 are discussed. Exposure tests were conducted under conditions that simulated auxiliary power unit operation. Weight gain and tensile strength data as a function of time of exposure at 650°C (1202°F) are reported. Fabrication of components with fiber metal acoustic materials is easily accomplished using standard roll forming and gas tungsten arc welding practices.

scholarly journals Method of coordinating air starter and auxiliary power unit joint operation

2020 ◽  
pp. 5-13
Author(s):  
Grigory Popov ◽  
◽  
Vasily Zubanov ◽  
Valeriy Matveev ◽  
Oleg Baturin ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Power Unit ◽  
Gas Turbine Engine ◽  
Working Process ◽  
Joint Operation ◽  
Turbine Engine ◽  
Auxiliary Power Unit ◽  
Auxiliary Power ◽  
Start Up ◽  
Air Turbine

The presented work provides a detailed description of the method developed by the authors for coordinating the working process of the main elements of the starting system for a modern gas turbine engine for a civil aviation aircraft: an auxiliary power unit (APU) and an air turbine – starter. This technique was developed in the course of solving the practical problem of selecting the existing APU and air turbine for a newly created engine. The need to develop this method is due to the lack of recommendations on the coordination of the elements of the starting system in the available literature. The method is based on combining the characteristics of the APU and the turbine, reduced to a single coordinate system. The intersection of the characteristic’s lines corresponding to the same conditions indicates the possibility of joint operation of the specified elements. The lack of intersection indicates the impossibility of joint functioning. The calculation also takes into account losses in the air supply lines to the turbine. The use of the developed method makes it possible to assess the possibility of joint operation of the APU and the air turbine in any operating mode. In addition to checking the possibility of functioning, as a result of the calculation, specific parameters of the working process at the operating point are determined, which are then used as initial data in calculating the elements of the starting system, for example, determining the parameters of the turbine, which in turn allow providing initial information for calculating the starting time or the possibility of functioning of the starting system GTE according to strength and other criteria. The algorithm for calculating the start-up time of the gas turbine engine was also developed by the authors and implemented in the form of an original computer program. Keywords: gas turbine engine start-up, GTE starting system, air turbine, methodology, joint work, auxiliary power unit, power, start-up time, characteristics matching, coordination, operational characteristics, computer program.

scholarly journals Off-Design Performances of an Organic Rankine Cycle for Waste Heat Recovery from Gas Turbines

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1105 ◽  
Author(s):  
Carlo Carcasci ◽  
Lapo Cheli ◽  
Pietro Lubello ◽  
Lorenzo Winchler
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Air Temperature ◽  
Mass Flow ◽  
Flow Rate ◽  
Power Output ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Ambient Air ◽  
Air Mass

This paper presents an off-design analysis of a gas turbine Organic Rankine Cycle (ORC) combined cycle. Combustion turbine performances are significantly affected by fluctuations in ambient conditions, leading to relevant variations in the exhaust gases’ mass flow rate and temperature. The effects of the variation of ambient air temperature have been considered in the simulation of the topper cycle and of the condenser in the bottomer one. Analyses have been performed for different working fluids (toluene, benzene and cyclopentane) and control systems have been introduced on critical parameters, such as oil temperature and air mass flow rate at the condenser fan. Results have highlighted similar power outputs for cycles based on benzene and toluene, while differences as high as 34% have been found for cyclopentane. The power output trend with ambient temperature has been found to be influenced by slope discontinuities in gas turbine exhaust mass flow rate and temperature and by the upper limit imposed on the air mass flow rate at the condenser as well, suggesting the importance of a correct sizing of the component in the design phase. Overall, benzene-based cycle power output has been found to vary between 4518 kW and 3346 kW in the ambient air temperature range considered.

Technological analysis and fuel consumption saving potential of different gas turbine thermodynamic configurations for series hybrid electric vehicles

2019 ◽  
Vol 234 (6) ◽  
pp. 1544-1562
Author(s):  
Wissam Bou Nader ◽  
Yuan Cheng ◽  
Emmanuel Nault ◽  
Alexandre Reine ◽  
Samer Wakim ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Fuel Consumption ◽  
Electric Vehicle ◽  
Power Unit ◽  
Hybrid Electric Vehicle ◽  
Auxiliary Power Unit ◽  
Auxiliary Power ◽  
Series Hybrid Electric Vehicle ◽  
Hybrid Electric ◽  
Technological Analysis

Gas turbine systems are among potential energy converters to substitute the internal combustion engine as auxiliary power unit in future series hybrid electric vehicle powertrains. Fuel consumption of these auxiliary power units in the series hybrid electric vehicle strongly relies on the energy converter efficiency and power-to-weight ratio as well as on the energy management strategy deployed on-board. This paper presents a technological analysis and investigates the potential of fuel consumption savings of a series hybrid electric vehicle using different gas turbine–system thermodynamic configurations. These include a simple gas turbine, a regenerative gas turbine, an intercooler regenerative gas turbine, and an intercooler regenerative reheat gas turbine. An energetic and technological analysis is conducted to identify the systems’ efficiency and power-to-weight ratio for different operating temperatures. A series hybrid electric vehicle model is developed and the different gas turbine–system configurations are integrated as auxiliary power units. A bi-level optimization method is proposed to optimize the powertrain. It consists of coupling the non-dominated sorting genetic algorithm to the dynamic programming to minimize the fuel consumption and the number of switching ON/OFF of the auxiliary power unit, which impacts its durability. Fuel consumption simulations are performed on the worldwide-harmonized light vehicles test cycle while considering the electric and thermal comfort vehicle energetic needs. Results show that the intercooler regenerative reheat gas turbine–auxiliary power unit presents an improved fuel consumption compared with the other investigated gas turbine systems and a good potential for implementation in series hybrid electric vehicles.

Evaluation of Axial Compressor Characteristics Under Overspray Condition

2013 ◽  
Author(s):  
Chihiro Myoren ◽  
Yasuo Takahashi ◽  
Manabu Yagi ◽  
Takanori Shibata ◽  
Tadaharu Kishibe
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Water Mass ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Test Facility ◽  
Compressor Performance ◽  
Water Mass Flow Rate

An axial compressor was developed for an industrial gas turbine equipped with a water atomization cooling (WAC) system, which is a kind of inlet fogging technique with overspray. The compressor performance was evaluated using a 40MW-class test facility for the advanced humid air turbine system. A prediction method to estimate the effect of WAC was developed for the design of the compressor. The method was based on a streamline curvature (SLC) method implementing a droplet evaporation model. Four test runs with WAC have been conducted since February 2012. The maximum water mass flow rate was 1.2% of the inlet mass flow rate at the 4th test run, while the design value was 2.0%. The results showed that the WAC decreased the inlet and outlet temperatures compared with the DRY (no fogging) case. These decreases changed the matching point of the gas turbine, and increased the mass flow rate and the pressure ratio by 1.8% and 1.1%, respectively. Since prediction results agreed with the results of the test run qualitatively, the compressor performance improvement by WAC was confirmed both experimentally and analytically. The test run with the design water mass flow rate is going to be conducted in the near future.

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