In order to satisfy operating requirements for constant core drilling technology in reverse circulation with hollow-through DTH,the power unit of G-3 engineering driller was ameliorated. The new one with dual channel ...In order to satisfy operating requirements for constant core drilling technology in reverse circulation with hollow-through DTH,the power unit of G-3 engineering driller was ameliorated. The new one with dual channel drive shaft, achieved the perfect assemble with transmission structure of the original power unit. It could interconvert according to need by using two sets of drive shafts with direct and reverse circulation. The repacked G-3 engineering driller carried on experiment in the field test in Luanchuan molybdenum mine of Henan, whose effect was very good.展开更多
当电网出现有功缺额并导致频率跌落时,风电机组可以通过释放自身轴系动能为电网提供短时频率支撑(short-term frequency support,STFS)。如何利用有限的风电机组轴系动能最大限度地支撑电网频率,是当前研究的热点问题。针对风电机组可...当电网出现有功缺额并导致频率跌落时,风电机组可以通过释放自身轴系动能为电网提供短时频率支撑(short-term frequency support,STFS)。如何利用有限的风电机组轴系动能最大限度地支撑电网频率,是当前研究的热点问题。针对风电机组可释放动能和电网频率变化率约束下的电网最大频率偏差最小化问题,该文提出一种基于有功功率互补控制(active-power complementation control,ACC)的风电机组STFS策略,揭示STFS过程中风电机组的最小动能释放机理,并证明采用ACC释放全部轴系动能的STFS策略为上述问题的最优解。最后,基于含风电的电网动模实验平台的实验结果验证该文提出STFS策略的可行性与频率支撑效果。展开更多
It’s well known that the performance of a gas turbine (efficiency, heat rate and power generated) is largely dependent on mass flow rate of air, inlet air temperature and turbine inlet temperature (TIT). As turbine i...It’s well known that the performance of a gas turbine (efficiency, heat rate and power generated) is largely dependent on mass flow rate of air, inlet air temperature and turbine inlet temperature (TIT). As turbine inlet temperature is dependent on quantity of burned fuel so that this factor is dropped out from this paper. It’s also known that gas turbines are constant volume machines i.e. at a given shaft speed they always move the same volume of air, but the power out-put of a turbine depends on the flow of mass through it. This is precisely the reason why on hot days, when air is less dense, power output falls off. A rise of one degree Centigrade temperature of inlet air decreases the power output by 1% and at the same time heat rate of the turbine also goes up. This is a matter of great concern to power producers. Many techniques have been developed to cool the inlet air to gas turbine. Some of these techniques to decrease the inlet air temperature are discussed here. The evaporative cooling technique is taken as a case study in this paper. A comparative studying is carried out between a unit using this technique and the same unit when the evaporative cooler is idle. The results advert to an increase in power output by 11.07% and a decrease in heat rate by approximately 4% when inlet air temperature drops from 50°C to 26°C.展开更多
The aim of the study is to determine the optimal structural parameters for a plastic centrifugal pump inducer within the framework of an orthogonal experimental method.For this purpose,a numerical study of the related...The aim of the study is to determine the optimal structural parameters for a plastic centrifugal pump inducer within the framework of an orthogonal experimental method.For this purpose,a numerical study of the related flow field is performed using CFX.The shaft power and the head of the pump are taken as the evaluation indicators.Accordingly,the examined variables are the thickness(S),the blade cascade degree(t),the blade rim angle(β1),the blade hub angle(β2)and the hub length(L).The impact of each structural parameter on each evaluation index is examined and special attention is paid to the following combinations:S2 mm,t 2,β1235°,β2360°and L 140 mm(corresponding to a maximum head of 98.15 m);S 5 mm,t 1.6,β1252°,β2350°and L 140 mm(corresponding to a minimum shaft power of 63.06 KW).Moreover,using least squares and fish swarm algorithms,the pump shaft power and head are further optimized,yielding the following optimal combination:S 5 mm,t 1.9,β1252°,β2360°and L 145 mm(corresponding to the maximum head of 91.90 m,and a minimum shaft power of 64.83 KW).展开更多
基金Project of Science & Technology Development Guidance of Jilin Province (No.200405033)
文摘In order to satisfy operating requirements for constant core drilling technology in reverse circulation with hollow-through DTH,the power unit of G-3 engineering driller was ameliorated. The new one with dual channel drive shaft, achieved the perfect assemble with transmission structure of the original power unit. It could interconvert according to need by using two sets of drive shafts with direct and reverse circulation. The repacked G-3 engineering driller carried on experiment in the field test in Luanchuan molybdenum mine of Henan, whose effect was very good.
文摘当电网出现有功缺额并导致频率跌落时,风电机组可以通过释放自身轴系动能为电网提供短时频率支撑(short-term frequency support,STFS)。如何利用有限的风电机组轴系动能最大限度地支撑电网频率,是当前研究的热点问题。针对风电机组可释放动能和电网频率变化率约束下的电网最大频率偏差最小化问题,该文提出一种基于有功功率互补控制(active-power complementation control,ACC)的风电机组STFS策略,揭示STFS过程中风电机组的最小动能释放机理,并证明采用ACC释放全部轴系动能的STFS策略为上述问题的最优解。最后,基于含风电的电网动模实验平台的实验结果验证该文提出STFS策略的可行性与频率支撑效果。
文摘It’s well known that the performance of a gas turbine (efficiency, heat rate and power generated) is largely dependent on mass flow rate of air, inlet air temperature and turbine inlet temperature (TIT). As turbine inlet temperature is dependent on quantity of burned fuel so that this factor is dropped out from this paper. It’s also known that gas turbines are constant volume machines i.e. at a given shaft speed they always move the same volume of air, but the power out-put of a turbine depends on the flow of mass through it. This is precisely the reason why on hot days, when air is less dense, power output falls off. A rise of one degree Centigrade temperature of inlet air decreases the power output by 1% and at the same time heat rate of the turbine also goes up. This is a matter of great concern to power producers. Many techniques have been developed to cool the inlet air to gas turbine. Some of these techniques to decrease the inlet air temperature are discussed here. The evaporative cooling technique is taken as a case study in this paper. A comparative studying is carried out between a unit using this technique and the same unit when the evaporative cooler is idle. The results advert to an increase in power output by 11.07% and a decrease in heat rate by approximately 4% when inlet air temperature drops from 50°C to 26°C.
基金project of the“The University Synergy Innovation Program of Anhui Province(GXXT-2019-004)”,“Natural Science Research Project of Anhui Universities(KJ2021ZD0144)”,“Wuhu Key R&D Project:Research and Industrialization of Intelligent Control Method of Engine Energy-Feeding Hydraulic Semi-Active Mount”.
文摘The aim of the study is to determine the optimal structural parameters for a plastic centrifugal pump inducer within the framework of an orthogonal experimental method.For this purpose,a numerical study of the related flow field is performed using CFX.The shaft power and the head of the pump are taken as the evaluation indicators.Accordingly,the examined variables are the thickness(S),the blade cascade degree(t),the blade rim angle(β1),the blade hub angle(β2)and the hub length(L).The impact of each structural parameter on each evaluation index is examined and special attention is paid to the following combinations:S2 mm,t 2,β1235°,β2360°and L 140 mm(corresponding to a maximum head of 98.15 m);S 5 mm,t 1.6,β1252°,β2350°and L 140 mm(corresponding to a minimum shaft power of 63.06 KW).Moreover,using least squares and fish swarm algorithms,the pump shaft power and head are further optimized,yielding the following optimal combination:S 5 mm,t 1.9,β1252°,β2360°and L 145 mm(corresponding to the maximum head of 91.90 m,and a minimum shaft power of 64.83 KW).
