The gas turbine blades with diffusion film cooling holes are newlydeveloped blade struc- tures in the hydrogen combustion gas turbine,which has an extremely high inlet gas temperature (1700 deg. C). TheFluid Machinery...The gas turbine blades with diffusion film cooling holes are newlydeveloped blade struc- tures in the hydrogen combustion gas turbine,which has an extremely high inlet gas temperature (1700 deg. C). TheFluid Machinery Laboratory of Nagoya Institute o Technology conductedfirstly a new research o the turbulent flow field over the gasturbine blade with diffusion film cooling holes in Japan. Normal-typeand X-ray hot wires were applied in the measurement of the flowfield.展开更多
Endwall film-cooling effectiveness experiments were conducted on a turbine guide vane using pressure sensitive paint measurement technique.Four film hole geometries,i.e.,a fan-shaped hole,a horizontal slot hole,and tw...Endwall film-cooling effectiveness experiments were conducted on a turbine guide vane using pressure sensitive paint measurement technique.Four film hole geometries,i.e.,a fan-shaped hole,a horizontal slot hole,and two vertical slot holes with different expansion angles,were tested under a film hole layout that considered the actual multi-chamber construction.A continuous slot was set upstream of the endwall film holes to examine the influence of the upstream cooling.The experiments were performed at a mainstream Reynolds number of620000,a mainstream turbulence intensity of 3.7%,and a coolant-to-mainstream density ratio of 1.5.The results showed that the vertical slot holes perform better in the various chamber zones on the endwall than other hole geometries,in particular the zone with highly accelerated mainstream and the zone with large orientation angle.The vertical slot hole with a large exit expansion angle always yields the highest effectiveness on the endwall.The upstream slot cooling remarkably improves the endwall effectiveness and the influences are almost consistent for various hole geometries.Compared with the baseline fan-shaped hole,from blowing ratios of 1.0 to 2.5,the increase in the area-averaged effectiveness by large expansion angle vertical slot hole reaches 10.7%-39.1%without upstream slot cooling,while with upstream slot cooling,the increase decreases to 4.9%-23.1%.The discharge coefficient of various hole geometries on the endwall has almost no difference at small blowing ratios,and the difference at medium and high blowing ratios is also not great.展开更多
The current geographic routing protocols arise data congestion if a multi-flow bypasses a hole simultaneously and excessive energy consumption of hole boundary nodes because these protocols tend to route data packets ...The current geographic routing protocols arise data congestion if a multi-flow bypasses a hole simultaneously and excessive energy consumption of hole boundary nodes because these protocols tend to route data packets along the boundaries of void areas （holes） by perimeter routing scheme.This scheme possibly enlarges the holes phenomenon （called hole diffusion problem） and shortens the life span of the network. A novel geographical routing algorithm based on a potential field approach （PFA） is proposed to deal with multiple holes scenario and restrict data to forward near boundary of a hole. That is, data packets are attracted to its sink and are repulsed away from the hole （s）. Simulation results show that PFA is superior to other protocols in terms of packet delivery ratio, network lifetime.展开更多
文摘The gas turbine blades with diffusion film cooling holes are newlydeveloped blade struc- tures in the hydrogen combustion gas turbine,which has an extremely high inlet gas temperature (1700 deg. C). TheFluid Machinery Laboratory of Nagoya Institute o Technology conductedfirstly a new research o the turbulent flow field over the gasturbine blade with diffusion film cooling holes in Japan. Normal-typeand X-ray hot wires were applied in the measurement of the flowfield.
基金supported by the financial support from National Science and Technology Major Project of China(J2019-Ⅲ-0007-0050)。
文摘Endwall film-cooling effectiveness experiments were conducted on a turbine guide vane using pressure sensitive paint measurement technique.Four film hole geometries,i.e.,a fan-shaped hole,a horizontal slot hole,and two vertical slot holes with different expansion angles,were tested under a film hole layout that considered the actual multi-chamber construction.A continuous slot was set upstream of the endwall film holes to examine the influence of the upstream cooling.The experiments were performed at a mainstream Reynolds number of620000,a mainstream turbulence intensity of 3.7%,and a coolant-to-mainstream density ratio of 1.5.The results showed that the vertical slot holes perform better in the various chamber zones on the endwall than other hole geometries,in particular the zone with highly accelerated mainstream and the zone with large orientation angle.The vertical slot hole with a large exit expansion angle always yields the highest effectiveness on the endwall.The upstream slot cooling remarkably improves the endwall effectiveness and the influences are almost consistent for various hole geometries.Compared with the baseline fan-shaped hole,from blowing ratios of 1.0 to 2.5,the increase in the area-averaged effectiveness by large expansion angle vertical slot hole reaches 10.7%-39.1%without upstream slot cooling,while with upstream slot cooling,the increase decreases to 4.9%-23.1%.The discharge coefficient of various hole geometries on the endwall has almost no difference at small blowing ratios,and the difference at medium and high blowing ratios is also not great.
文摘The current geographic routing protocols arise data congestion if a multi-flow bypasses a hole simultaneously and excessive energy consumption of hole boundary nodes because these protocols tend to route data packets along the boundaries of void areas （holes） by perimeter routing scheme.This scheme possibly enlarges the holes phenomenon （called hole diffusion problem） and shortens the life span of the network. A novel geographical routing algorithm based on a potential field approach （PFA） is proposed to deal with multiple holes scenario and restrict data to forward near boundary of a hole. That is, data packets are attracted to its sink and are repulsed away from the hole （s）. Simulation results show that PFA is superior to other protocols in terms of packet delivery ratio, network lifetime.
