Based on the EAST equilibrium,the effects of boron(B)and neon(Ne)injected at different locations on the target heat load,and the distributions of B and Ne particles were investigated by transport code SOLPS-ITER.It wa...Based on the EAST equilibrium,the effects of boron(B)and neon(Ne)injected at different locations on the target heat load,and the distributions of B and Ne particles were investigated by transport code SOLPS-ITER.It was found that the B injection was more sensitive to the injection location for heat flux control than impurity Ne.The high electron and ion densities near the inner target in the discharge with impurity B injected from over X-point(R_(1))led to plasma detachment only at the inner target,and the localized B ions in the cases with injection from outer target location(R_(2))and upstream location(R_(3))led to far-SOL detachment at the outer target,but not at the inner target.In contrast,for Ne,the spatial distributions of Ne ions and electrons were found to be similar in all the cases at the three injection locations,and the detached plasma was achieved at the inner target and the electron temperature was reduced at the outer target.For locations R_(2) and R_(3),impurity B showed a more pronounced effect on the heat flux at the far-SOL of the outer target.Further analysis indicated that Ne atoms came mainly from the recycling sources,whereas B atoms came mainly from injection,and that their distinct atomic distributions resulted from the difference in the ionization threshold and ionization mean free path.In addition,the radiation proportion of B in the divertor region was larger than that of Ne when the total radiation power was similar,which suggests that B has less influence on the core region.展开更多
The flow structure of the vortex cooling is asymmetrical compared to the traditional gas turbine leading edge cooling,such as the impingement cooling and the axial flow cooling.This asymmetrical property will affect t...The flow structure of the vortex cooling is asymmetrical compared to the traditional gas turbine leading edge cooling,such as the impingement cooling and the axial flow cooling.This asymmetrical property will affect the cooling performance in the blade leading edge,whereas such effects are not found in most of the studies on vortex cooling due to the neglect of the mainstream flow in the airfoil channel.This study involves the mainstream flow field and the rotational effects based on the profile of the GE E3 blade to reveal the mechanism of the asymmetrical flow structure effects.The nozzle position on the characteristics of the vortex and film composite cooling in the turbine rotating blade leading edge is numerically investigated.The cool-ant injecting nozzles are set at the side of the pressure surface(PS-side-in)vs.that is set at the side of the suction surface(SS-side-in)to compare the cooling characteristics at the rotating speed range of 0–4000 rpm with fluid and thermal conjugate approach.Results show that the nozzle position presents different influences under low and higher rotational speeds.As for the mainstream flow,rotation makes the stagnation line move from the pressure surface side to the suction surface side,which changes the coolant film attachment on the blade leading edge surface.The position of nozzles,however,indicates limited influence on the coolant film flow.As for the internal channel vortex flow characteristics,the coolant injected from the nozzles forms a high-velocity region near the target wall,which brings about enhancing convective heat transfer.The flow direction of the vortex flow near the internal channel wall is opposite and aligns with the direction of Coriolis force in both the PS-side-in and SS-side-in,respectively.Therefore,the Coriolis force augments the convective heat transfer intensity of the vortex cooling in the internal channel in SS-side-in while weakening the internal heat transfer in PS-side-in.Such effects become more intense with higher rotational speed.The blade surface temperature decreases as the Coriolis force increases the internal heat transfer intensity.The SS-side-in suggests a superior composite cooling performance under the relatively higher rotating speed.The SS-side-in structure is recommended in the gas turbine blade leading edge running at a higher rotating speed.展开更多
This paper presents a numerical investigation of an active tip-clearance control method based on cooling injectionfrom the blade tip surface. It aims to study the influences of air injection on controlling tip clearan...This paper presents a numerical investigation of an active tip-clearance control method based on cooling injectionfrom the blade tip surface. It aims to study the influences of air injection on controlling tip clearance flow, withemphasis on the effects of the injection location on secondary flow and the potential thermal benefits from thecooling jet. The results show that injection location plays an important role in the redistribution of secondary flowwithin the cascade passage. Injection located much closer to the pressure-side comer performs better in reducingtip clearance massflow and its associated losses. However, it also intensifies tip passage vortex, due to less restraintderiving from the reduced tip clearance vortex. Lower plenum total pressure is required to inject equivalentamount of cooling air, but the heat transfer condition on the blade tip surface is a bit worse than that with injectionfrom the reattachment region. Thus the optimum location of air injection should be at the tip separation vortex region.展开更多
基金Project supported by the National Key R&D Program of China(Grant No.2019YFE03030004)the National Natural Science Foundation of China(Grant No.12275040)+1 种基金the Users with Excellence Program of Hefei Science Center CAS(Grant No.2020HSC-UE010)This research is also sponsored in part by the U.S.Department of Energy under contract DEAC02-09CH11466.
文摘Based on the EAST equilibrium,the effects of boron(B)and neon(Ne)injected at different locations on the target heat load,and the distributions of B and Ne particles were investigated by transport code SOLPS-ITER.It was found that the B injection was more sensitive to the injection location for heat flux control than impurity Ne.The high electron and ion densities near the inner target in the discharge with impurity B injected from over X-point(R_(1))led to plasma detachment only at the inner target,and the localized B ions in the cases with injection from outer target location(R_(2))and upstream location(R_(3))led to far-SOL detachment at the outer target,but not at the inner target.In contrast,for Ne,the spatial distributions of Ne ions and electrons were found to be similar in all the cases at the three injection locations,and the detached plasma was achieved at the inner target and the electron temperature was reduced at the outer target.For locations R_(2) and R_(3),impurity B showed a more pronounced effect on the heat flux at the far-SOL of the outer target.Further analysis indicated that Ne atoms came mainly from the recycling sources,whereas B atoms came mainly from injection,and that their distinct atomic distributions resulted from the difference in the ionization threshold and ionization mean free path.In addition,the radiation proportion of B in the divertor region was larger than that of Ne when the total radiation power was similar,which suggests that B has less influence on the core region.
基金supported by the National Science and Technology Major Project under Grant (2017-I-0009-0010).
文摘The flow structure of the vortex cooling is asymmetrical compared to the traditional gas turbine leading edge cooling,such as the impingement cooling and the axial flow cooling.This asymmetrical property will affect the cooling performance in the blade leading edge,whereas such effects are not found in most of the studies on vortex cooling due to the neglect of the mainstream flow in the airfoil channel.This study involves the mainstream flow field and the rotational effects based on the profile of the GE E3 blade to reveal the mechanism of the asymmetrical flow structure effects.The nozzle position on the characteristics of the vortex and film composite cooling in the turbine rotating blade leading edge is numerically investigated.The cool-ant injecting nozzles are set at the side of the pressure surface(PS-side-in)vs.that is set at the side of the suction surface(SS-side-in)to compare the cooling characteristics at the rotating speed range of 0–4000 rpm with fluid and thermal conjugate approach.Results show that the nozzle position presents different influences under low and higher rotational speeds.As for the mainstream flow,rotation makes the stagnation line move from the pressure surface side to the suction surface side,which changes the coolant film attachment on the blade leading edge surface.The position of nozzles,however,indicates limited influence on the coolant film flow.As for the internal channel vortex flow characteristics,the coolant injected from the nozzles forms a high-velocity region near the target wall,which brings about enhancing convective heat transfer.The flow direction of the vortex flow near the internal channel wall is opposite and aligns with the direction of Coriolis force in both the PS-side-in and SS-side-in,respectively.Therefore,the Coriolis force augments the convective heat transfer intensity of the vortex cooling in the internal channel in SS-side-in while weakening the internal heat transfer in PS-side-in.Such effects become more intense with higher rotational speed.The blade surface temperature decreases as the Coriolis force increases the internal heat transfer intensity.The SS-side-in suggests a superior composite cooling performance under the relatively higher rotating speed.The SS-side-in structure is recommended in the gas turbine blade leading edge running at a higher rotating speed.
文摘This paper presents a numerical investigation of an active tip-clearance control method based on cooling injectionfrom the blade tip surface. It aims to study the influences of air injection on controlling tip clearance flow, withemphasis on the effects of the injection location on secondary flow and the potential thermal benefits from thecooling jet. The results show that injection location plays an important role in the redistribution of secondary flowwithin the cascade passage. Injection located much closer to the pressure-side comer performs better in reducingtip clearance massflow and its associated losses. However, it also intensifies tip passage vortex, due to less restraintderiving from the reduced tip clearance vortex. Lower plenum total pressure is required to inject equivalentamount of cooling air, but the heat transfer condition on the blade tip surface is a bit worse than that with injectionfrom the reattachment region. Thus the optimum location of air injection should be at the tip separation vortex region.
