04041 Flow visualization of longitudinal vortices induced by an inclined impinging jet in a crossflow-effective cooling of high temperature gas turbine blades

04041 Flow visualization of longitudinal vortices induced by an inclined impinging jet in a crossflow-effective cooling of high temperature gas turbine blades

10 Engines (power generation and propulsion, electrical vehicles) Effects of pressure on fuel-rich combustion of 97104038 methane-air under high ...

213KB Sizes 2 Downloads 7 Views

10

Engines

(power generation

and propulsion,

electrical vehicles)

Effects of pressure on fuel-rich combustion of 97104038 methane-air under high pressure Yamamoto, T. et al. Energy Comers. Mgmr, 1997, 38, (10-13) A new and innovative gas turbine system is proposed in this paper. It is called the chemical gas turbine system and would improve the thermal efficiency more than 10% in comparison to conventional systems. This gas turbine system is based on promising developments in fuel-rich combustors with a carbon fibre reinforced carbon composite (C/C composite) for the turbine blades. One fundamental research area in the system development was the design of a 4 MPa-scale combustor with methane-air. Flammability limit, components of combustion gases and combustion temperature were measured between 1.1 and 4.1 MPa in pressure. Results from these measurements are reported. Externally-fired combined cycle: an effective coal 97104039 fueled technology for repowering and new generation Stoddard, L. E. et al. Proc. Int. Tech. Con$ Coal Ml. Fuel Sysf., 1995, 20, 697-707. The paper claims the externally-fired combined cycle (EFCC) is an attractive emerging technology for powering high efficiency combined gas and steam turbine cycles with coal or other ash bearing fuels. In the EFCC, the heat input to a gas turbine is supplied indirectly through a ceramic air heater, which, along with an atmospheric coal combustor and ancillary equipment, replaces the conventional gas turbine combustor. A steam generator located downstream from the ceramic air heater and steam turbine cycle, along with an exhaust cleanup system, completes the combined cycle. The Kennebunk Test Facility (KTF) has recently begun operation, hitherto employing natural gas, commencing operation with coal in early 1995. The US Department of Energy selected an EFCC repowering of the Pennsylvania Electricity Company’s Warren Station for funding under the Clean Coal Technology Program Round V. The project focuses on repowering an existing 48 MW (gross) steam turbine with an EFCC power island incorporating a 30 MW gas turbine, for a grass power output of 78 MW and a net output of 72 MW. Use of a dry scrubber and fabric filter will reduce Air Act Amendments of 1990 and nitrogen oxides emissions are controlled by the use of staged combustion. Start-up is scheduled for 1997. First and Second Law analysis of diesel engines 97l04040 and gas turbines in combined cycles: a comparative study Ferrari, J. R. et al. Proc. Am. Power Conf. 1997, 59, (2), 847-852. A First and Second Law analysis of a single diesel engine and a single gas turbine in combined cycle with supplemental firing in a burner is presented. The effects of steam pressure and temperature on system performance are explored, as are the effects of changing the pinch point and stack temperature. Greater combined cycle power production arises from a higher exhaust temperature and mass flow of the gas turbine. The better efficiency of the diesel engine delivers increased combined cycle efficiency. Supplemental firing of the exhaust gas from each engine is shown to increase combined cycle efficiency until a maximum is reached. Beyond the point of maximum efficiency, burner fuel addition is shown to increase boiler irreversibilities, delivering a sharp drop in combined cycle efficiency. Flow visualization of longitudinal vortices induced 97iQ4041 by an inclined impinging jet in a crossflow-effective cooling of high temperature gas turbine blades Nakabe, K. et al. Enerby Cowers. Mgmt, 1997, 38, (lo-13), 1145-1153. Energy conversion efficiency can be improved by raising the working temperature of a gas turbine and in order to realize high temperature gas turbines, development of effective cooling system of turbine blades is indispensable. The use of longitudinal vortices to enhance the heat transfer from the inner surfaces of turbine blades was considered. Their effectiveness was already confirmed for the case of a disturbed flat plate boundary layer with the insertion of a wing-type vortex generator (WVG) attached to a large-eddy-break-up (LEBU) plate. However, there was substantial pressure loss due to a form drag of the WVG. Longitudinal vortices generated by an inclined jet (VG jet) into crossflow have been examined to apply for effective cooling of gas turbine blades. Flow visualization and heat transfer experiments were conducted for a duct flow. It was experimentally demonstrated that jet impingement is effective for heat transfer augmentation even in the case with crossflow, and that the longitudinal vortices have been confirmed to be generated by the insertion of the VG jet. The generated vortices are expected to effectively enhance the heat transfer from the inner surface of the blades of a gas turbine. Gas turbine combustion: prospects and challenges 97l04042 Gupta, A. K. Energy Comers. Mgmt, 1997, 38, (10-13) 1311-1318 Gas turbines became engineering reality in the late 193Os, about two decades after they were first proposed. The two families of gas turbines, aircraft and stationary, share a certain similarity, although their design requirements are significantly different. Despite the many advances in combustor design, new concepts and technology are still needed to satisfy the current and projected pollutants emission regulations and to provide energy conservation. Specifically, ultra-low NO, combustor technology is required to meet the ozone depletion challenge. Researchers are facing concerns about the development of dry low-NO, stationary and aero engines. For advanced concepts for environmental pollution control, fundamental combustion research needs to be done in the areas of interactions between droplet, turbulence and chemistry, computer model

340

Fuel and Energy Abstracts

September

1997

development, gas and solid phase kinetics, droplet/droplet interaction, soot formation and chemistry, and flame structure. Future combustors are expected to be even shorter and lighter than they are today, operate at higher temperatures and pressures and utilize a much broader range of fuels. Applied combustion research needs include, clean and energy efficient combustion of a broad range of fuels and the associated reduction of pollution through combustion control. Both experimental and theoretical combustion engineers need greater understanding of the combustion processes. Gas turbine engines will find even greater use in power plants in the future due to their low environmental impact and natural resource conservation. 97104043 Generation of free momentum and free energy by the help of centrifugal forces Marinov, S. J. New Energy, 1997, 2, (1). 44-59. Substantial differences exist between potential and inertial forces. By the help of centrifugal forces, it is possible to generate free momentum and free energy; energy can thus be generated from nothing. Perpetual motion machines are presented: the ‘Segner-Marinov-turbine,‘, the ‘BuhlerMarinov generator’ and the ‘Deisting-Marinov machine’. The first small Segner-Marinov turbine, which was recently constructed, demonstrates the effect of self-acceleration, but since the friction torque overwhelms the driving torque, it still does not rotate as a perpetuum mobile. ‘Deisting drives,’ a simple variation of the well-known ‘Buhler drive’. constructed by Joerg and Friedrich Deisting in Graz in the last decade produce free momentum. The author is working now on the Deisting-Marinov machine in the hope of producing the requisite energy for providing the inertial forces to propel the machine.

97104044 High pertormance power systems (HIPPS) for the 21st century Robson, F. L. et al. hoc. ht. Tech. Conf Coal Util. Fuel Sysr., 1997, 22, 183-193. In the Combustion 2000 Program, sponsored by DOEIPETC, a team led by United Technologies Research Center identified a 300 MW High Performance Power Systems (HIPPS) which met the DOE goals of 47%) efficiency, emissions of 10% NSPS, and costs lower than a PC-fired steam station. This HIPPS was based on a commercially available heavy frame gas turbine in the 1996-97 time frame. As part of the HIPPS Phase II program, advanced aero-derivative gas turbines have been investigated for use in HIPPS that could appear in the latter part of the first decade of the 21st century. These engine configurations are based an the EPRIiUtility Consortium-sponsored Collaborative Advanced Gas Turbine (CAGT) programme. This uses technology from the latest 80-100,000 lb thrust aero engines, but incorporate industrial features that could allow turbine temperature approaching 3000°F and pressure ratios over 5011. A variety of engine configurations and power cycles were analysed for use in the advanced HIPPS. For systems having one gas turbine, power outputs were in the 150 MW to 300 MW range with efficiencies of 45% to 55% (HHV) depending on application and cycle variation.

97104045 Hydrogen gas-turbine characteristics and hydrogen energy system schemes Kato, S. and Nomura, N. Energy Cortvers. Mgmf, 1997, 38, (lo-13), 13191326. A practical candidate in constructing an alternative hydrogen energy system element is the small-sized hydrogen gas-turbine ortginated from a lightweight car turbo-charger. Its energetic characteristics were experimentally examined and the potential of alternative hydrogen energy systems including hydrogen gas-turbines are also investigated from the standpoint of usage, regeneration, transportation, storage and of wasted heat reutilization including environmental load reduction. Several hydrogen energy schemes are also disclosed in this paper. Increasing the effectiveness of coal-fired power 97104046 plants using fuel cells Kotowski, W. et al. Gospod. Paliwami Energ., 1997, 45, (2), 9-12, 17. (In Polish) Coal gasification combined cycle power generation using gas turbine-driven generators or fuel cells in a combination with steam turbine-driven generators is reviewed.

97104047 Influence of internal heat leak on the power versus efficiency characteristics of heat engines Chen, L. et al. Energy Comers. Mgmt., 1997, 38, (14), 1501-1507. The optimal performance of heat engines is affected by an internal leak, and the influence of such an occurrence is examined in this paper. The relation between optimal power output and efficiency is derived for a steady state irreversible heat engine with irreversibilities due to external heat resistance and internal heat leak. The power versus efficiency characteristics obtained in this paper are qualitatively different from those of an endoreversible heat engine. Furthermore, good agreement is observed with the characteristics of a real heat engine.