Satoshi Hada

Evolution and Future Trend of Large Frame Gas Turbines: A New 1600 Degree C, J Class Gas Turbine

MHI recently developed a 1600°C class J-type gas turbine, utilizing some of the technologies developed in the National Project to promote the development of component technology for the next generation 1700°C class gas turbine.This new frame is expected to achieve higher combined cycle efficiency and will contribute to reduce CO2 emissions.The target combined cycle efficiency of the J type gas turbine will be above 61.5% (gross, ISO standard condition, LHV) and the 1on1 combined cycle output will reach 460MW for 60Hz engine and 670MW for 50Hz engine.This new engine incorporates:1) A high pressure ratio compressor based on the advanced M501H compressor, which was verified during the M501H development in 1999 and 2001.2) Steam cooled combustor, which has accumulated extensive experience in the MHI G engine (> 1,356,000 actual operating hours).3) State-of-art turbine designs developed through the 1700°C gas turbine component technology development program in Japanese National Project for high temperature components.This paper discusses the technical features and the updated status of the J-type gas turbine, especially the operating condition of the J-type gas turbine in the MHI demonstration plant, T-Point.The trial operation of the first M501J gas turbine was started at T-point in February 2011 on schedule, and major milestones of the trial operation have been met. After the trial operation, the first commercial operation has taken place as scheduled under a predominantly Daily-Start-and-Stop (DSS) mode. Afterward, MHI performed the major inspection in October 2011 in order to check the mechanical condition, and confirmed that the hot parts and other parts were in sound condition.Copyright

Computational Study of a Midpassage Gap and Upstream Slot on Vane Endwall Film-Cooling

mance. To reduce NOx resulting from combustion, designs for combustors attempt to achieve flat pattern factors that results in high levels of heat transfer to the endwall of the first stage vane. Film-cooling is still one of the most effective cooling methods for many component features including the endwall. This paper presents results from a computational study of a film-cooled endwall. The endwall design considers both an upstream slot, representing the combustor—turbine junction, and a midpassage slot, representing the mating between the adjacent vanes. The focus of this study is on comparing adiabatic effectiveness levels on the endwall with varying leakage flowrates and gap widths. Results indicate reasonable agreement between computational predictions and experimental measurements of adiabatic effectiveness levels along the endwall. The results of this study show that the midpassage slot has a large influence on the coolant coverage. It was also shown that by raising the combustor relative to the downstream vane endwall, better coolant coverage from the combustor-turbine slot could be achieved. DOI: 10.1115/1.4001135

Effects of an Axisymmetric Contoured Endwall on a Nozzle Guide Vane: Convective Heat Transfer Measurements

Heat transfer is a critical factor in the durability of gas turbine components, particularly in the first vane. An axisymmetric contour is sometimes used to contract the cross sectional area from the combustor to the first stage vane in the turbine. Such contouring can lead to significant changes in the endwall flows, thereby altering the heat transfer. This paper investigates the effect of axisymmetric contouring on the endwall heat transfer of a nozzle guide vane. Heat transfer measurements are performed on the endwalls of a planar and contoured passage whereby one endwall is modified with a linear slope in the case of the contoured passage. Included in this study is upstream leakage flow issuing from a slot normal to the inlet axis. Each of the endwalls within the contoured passage presents a unique flow field. For the contoured passage, the flat endwall is subject to an increased acceleration through the area contraction, while the contoured endwall includes both increased acceleration and a turning of streamlines due to the slope. Results indicate heat transfer is reduced on both endwalls of the contoured passage relative to the planar passage. In the case of all endwalls, increasing leakage mass flow rate leads to an increase in heat transfer near the suction side of the vane leading edge. DOI: 10.1115/1.4002966

Effects of an Axisymmetric Contoured Endwall on a Nozzle Guide Vane: Adiabatic Effectiveness Measurements

Gas turbine designs seek improved performance by modifying the endwalls of nozzle guide vanes in the engine hot section. Within the nozzle guide vanes these modifications can be in the form of an axisymmetric contour as the area contracts from the combustor to the turbine. This paper investigates the effect of axisymmetric endwall contouring on the cooling performance of a film cooled endwall. Adiabatic effectiveness measurements were performed in a planar passage for comparison to a contoured passage whereby the exit Reynolds numbers was matched. For the contoured passage, measurements were performed on both the flat endwall and on the contoured endwall. Fully expanded film cooling holes were distributed on the endwall surface preceded by a twodimensional slot normal to the inlet axis. Results indicated that the coolant coverage from the upstream leakage slot was spread over a larger area of the contoured endwall in comparison to the flat endwall of the planar passage. Film cooling effectiveness on the flat endwall of the contoured passage showed minimal differences relative to the planar passage results. The contracting endwall of the contoured passage, however, showed a significant reduction with average film cooling effectiveness levels approximately 40% lower than the planar passage at low film cooling flow rates. In the case of all endwalls, increasing leakage and film cooling mass flow rates led to an increase in cooling effectiveness and coolant coverage. NOMENCLATURE Ah area of film cooling hole C true vane chord CD discharge coefficient Cp pressure coefficient, (Ps – Ps,in)/0.5ρU 2

The Effect of Leading Edge Diameter on the Horse Shoe Vortex and Endwall Heat Transfer

The endwall of the first stage vane / blade of modern high temperature gas turbine has been exposed to severe heat transfer environments. Due to the formation of a horse shoe vortex (HV), the flow field of a vane and blade leading edge juncture to endwall is especially complicated and it is difficult to estimate the heat transfer coefficients and the film cooling effectiveness levels in this area. This paper describes the results of experimental and numerical studies on the heat transfer and flow dynamics in the leading edge endwall region of a symmetric airfoil. The effects of inlet velocity, boundary layer thickness and leading edge diameter of a symmetric airfoil were investigated on the endwall heat transfer in a low speed wind tunnel facility. The time averaged local heat transfer coefficients were measured by naphthalene sublimation method and the instantaneous velocity field was obtained by Particle Image Velocimetry (PIV). As the leading edge diameter of symmetric airfoil decreases, the heat transfer coefficients on an endwall increases and is proportional to Re0.71 that is base on the leading edge diameter. However, the boundary layer thickness was found to have a marginal effect on the endwall heat transfer.Copyright

Film Cooling With Swirling Coolant Flow Controlled by Impingement Cooling in a Closed Cavity

A new film cooling concept has been developed by managing the swirled film coolant induced inside a hexagonal plenum by two slant impingement jets, which are inclined at α degree toward the vertical direction and installed in a staggered position on the plenum chamber wall. Film cooling tests have been conducted by using a circular film cooling hole model mounted on a low speed wind tunnel. Heat transfer coefficient distributions of inclined jet impingements in a closed cavity was measured by naphthalene sublimation method and the film cooling effectiveness on the surface of the wind tunnel was measured by pressure sensitive paint (PSP). It appeared from experimental results that the swirled film coolant flow deteriorated the film cooling effectiveness at low swirl number but improved it at high swirl number. To investigate the mechanism of the improved film cooling effectiveness by the swirled coolant, the spatial distribution of the film cooling effectiveness and flow field were measured by laser induced fluorescence (LIF) and particle image velocimetry (PIV), respectively. The coolant jet penetration into mainstream is suppressed by the strong swirling motion of the coolant. As a result the film cooling effectiveness distribution on the wall keeps higher value behind the cooling hole over a long range. Additionally, kidney vortex structure was disappeared at high swirl number.Copyright