Micro-turbine engine has no enough space for measuring impeller characteristics,so the design and the construction of a new test facility of micro-turbo-machinery are presented for micro-centrifugal compressors and ra...Micro-turbine engine has no enough space for measuring impeller characteristics,so the design and the construction of a new test facility of micro-turbo-machinery are presented for micro-centrifugal compressors and radial turbines.The facility is used for the full speed compressor test and the long duration hot turbine test.To rapidly adjust the testing condition,all regulations of the operating state are automatically completed by the control system.The facility is also used for testing the impeller performance with a series of diameter from 55 mm to 180 mm as a result of the modular design.A thermal protection system is designed to avoid the heat distortion caused by the high turbine inlet temperature over 1 100 K and provide a proper experimental environment for the electronic components.A photoelectric torque transducer with the accuracy of 1% is designed to measure the torque of rigid shaft at a high speed of 125 000 r/min.The designing techniques for micro-turbo-machineries are verified by the impeller testing of the facility.展开更多
According to a research on the 30kVA simulation experimental platform of hydraulic wind tur- bine, its basic structure, composition and operation principle are expounded in this paper. An in- verter motor is used to s...According to a research on the 30kVA simulation experimental platform of hydraulic wind tur- bine, its basic structure, composition and operation principle are expounded in this paper. An in- verter motor is used to simulate the wind turbine, while a similarity calculation method is applied be- tween the small and large wind turbine. A fixed displacement pump-variable motor closed loop is used as the main transmission system, and a self-excited synchronous generator generates electricity through the grid connection. The experiment and simulation study on the speed and power control of the hydraulic wind turbine is conducted, based on the experimental platform, thus correctness and progressiveness of the experiment platform is further verified. The experimental platform study lays a foundation for further research on the characteristics of hydraulic wind turhln~展开更多
There is distinct difference in the tangential wind profile between different typhoons in the western North Pacific. At present, only two parameters, maximum wind and radius of maximum wind, are used in NCAR-AFWA bogu...There is distinct difference in the tangential wind profile between different typhoons in the western North Pacific. At present, only two parameters, maximum wind and radius of maximum wind, are used in NCAR-AFWA bogus for MM5 mesoscale numerical model. As a result, sometimes the outer structure of typhoon cannot be described accurately. The tangential wind profile of NCAR-AFWA bogus is improved by introducing radii of 25.7 m/s and 15.4 m/s, and then the track and intensity of Typhoon Nockten (No.0425) are simulated. The results show that the simulations of track and intensity of typhoon both have been improved by simultaneously introducing the radii in the tangential wind profile of typhoon bogus. At the same time, there is improvement in the gale wind range of the typhoon simulated.展开更多
Observational data of the severe typhoon Hagupit are obtained by a 3-dimensional ultrasonic anemometer which is installed on a 100-meter-high meteorological tower located at an islet off the coast of Guangdong.The cha...Observational data of the severe typhoon Hagupit are obtained by a 3-dimensional ultrasonic anemometer which is installed on a 100-meter-high meteorological tower located at an islet off the coast of Guangdong.The characteristics of the extreme wind load parameters for offshore wind turbines under the influence of extreme winds at severe typhoon intensity are analyzed.By comparing the observed data with the results derived from the International Electrotechnical Commission (IEC) standard 61400-1,the applicability of the methods computing extreme wind load parameters in the IEC standard are investigated under typhoon conditions.The results are as follows.(1) The changes of both the offshore extreme gust wind speeds and the extreme wind directions render a "M" shape bi-modal distribution with peak values in the eyewall region of Hagupit.(2) There are significant differences of amplitudes of the observed extreme operating gust wind speeds and extreme wind direction from the results calculated from the IEC standard.(3) The amplitudes of both the extreme operating gust wind speeds and the extreme directions exceed the upper limits of the IEC standard for three standard classes of wind turbines,and the values calculated by IEC standard are much significantly larger than the measured ones.(4) The observed extreme operating gust wind speeds are consistent with the results calculated by the IEC standard when wind turbines are under full or partial workload or cut-off conditions,although the amplitude of extreme wind directions calculated in terms of the IEC standard is larger than that of direct measurements.Measured extreme operating gust wind speeds sometimes exceed the IEC design criteria.展开更多
Article use Visual LISP development tools and DCL dialog technology, which implements the standard straight teeth, a two- dimensional cylindrical gear paranaetric drawing on AutoCAD platform, with easy to operate and ...Article use Visual LISP development tools and DCL dialog technology, which implements the standard straight teeth, a two- dimensional cylindrical gear paranaetric drawing on AutoCAD platform, with easy to operate and improve design efficiency. We achieved that using the dialog box design input parameters, and gear parts of the design calculations, parameters proofreading and all kinds of gear design drawing different structures by programming. The output is fully automated computer-aided design system. The results show that the design of the system significantly improves the efficiency of the part design.展开更多
This paper introduces a new study on the optimum calculation of partial transmission ratios of mechanical drive system using a V-belt and two-step bevel helical gearbox for getting minimum size of the system. In the p...This paper introduces a new study on the optimum calculation of partial transmission ratios of mechanical drive system using a V-belt and two-step bevel helical gearbox for getting minimum size of the system. In the paper, based on moment equilibrium condition of a mechanic system including V-belt and a two-gear-unit of the gearbox, models for optimum calculation of the partial ratios of the V-belt and the gearbox were proposed. As the models are explicit, the partial ratios can be calculated accurately and simply.展开更多
This study examines experimentally the effect of stators on the performance and heat transfer characteristics of small axial cooling fans. A single fan impeller, followed by nine stator blades in the case of a complet...This study examines experimentally the effect of stators on the performance and heat transfer characteristics of small axial cooling fans. A single fan impeller, followed by nine stator blades in the case of a complete stage, was used for all the experimental configurations. Performance measurements were carried out in a constant speed stage performance test rig while the transient liquid crystal technique was used for the heat transfer measurements. Full surface heat transfer coefficient distributions were obtained by recording the temperature history of liquid crystals on a target plate. The experimental data indicated that the results are highly affected by the flow conditions at the fan outlet. Stators can be beneficial in terms of pressure drop and efficiency, and thus more economical operation, as well as, in the local heat transfer distribution at the wake of the stator blades if the fan is installed very close to the cooling object. However, as the separation distance increases, enhanced heat transfer rate in the order of 25% is observed in the case of the fan impeller.展开更多
基金Supported by the National Natural Science Foundation of China(50576034)~~
文摘Micro-turbine engine has no enough space for measuring impeller characteristics,so the design and the construction of a new test facility of micro-turbo-machinery are presented for micro-centrifugal compressors and radial turbines.The facility is used for the full speed compressor test and the long duration hot turbine test.To rapidly adjust the testing condition,all regulations of the operating state are automatically completed by the control system.The facility is also used for testing the impeller performance with a series of diameter from 55 mm to 180 mm as a result of the modular design.A thermal protection system is designed to avoid the heat distortion caused by the high turbine inlet temperature over 1 100 K and provide a proper experimental environment for the electronic components.A photoelectric torque transducer with the accuracy of 1% is designed to measure the torque of rigid shaft at a high speed of 125 000 r/min.The designing techniques for micro-turbo-machineries are verified by the impeller testing of the facility.
基金Supported by the National Key Basic Research Development Program of China(No.2014CB046405)the National Natural Science Foundation of China(No.51475406,51405423)the Hebei Youth Fund(No.QN20132017)
文摘According to a research on the 30kVA simulation experimental platform of hydraulic wind tur- bine, its basic structure, composition and operation principle are expounded in this paper. An in- verter motor is used to simulate the wind turbine, while a similarity calculation method is applied be- tween the small and large wind turbine. A fixed displacement pump-variable motor closed loop is used as the main transmission system, and a self-excited synchronous generator generates electricity through the grid connection. The experiment and simulation study on the speed and power control of the hydraulic wind turbine is conducted, based on the experimental platform, thus correctness and progressiveness of the experiment platform is further verified. The experimental platform study lays a foundation for further research on the characteristics of hydraulic wind turhln~
基金Experiments on coupling typhoons, waves and storm surges in the South China Sea andpreviews of typhoon-inflicted disasters, a project from the research foundation for the science of tropical andmarine meteorology
文摘There is distinct difference in the tangential wind profile between different typhoons in the western North Pacific. At present, only two parameters, maximum wind and radius of maximum wind, are used in NCAR-AFWA bogus for MM5 mesoscale numerical model. As a result, sometimes the outer structure of typhoon cannot be described accurately. The tangential wind profile of NCAR-AFWA bogus is improved by introducing radii of 25.7 m/s and 15.4 m/s, and then the track and intensity of Typhoon Nockten (No.0425) are simulated. The results show that the simulations of track and intensity of typhoon both have been improved by simultaneously introducing the radii in the tangential wind profile of typhoon bogus. At the same time, there is improvement in the gale wind range of the typhoon simulated.
基金National Natural Science Foundation of China (90715031,40775071)Public Benefit Research Foundation of Ministry of Science and Technology (GYHY200806012)
文摘Observational data of the severe typhoon Hagupit are obtained by a 3-dimensional ultrasonic anemometer which is installed on a 100-meter-high meteorological tower located at an islet off the coast of Guangdong.The characteristics of the extreme wind load parameters for offshore wind turbines under the influence of extreme winds at severe typhoon intensity are analyzed.By comparing the observed data with the results derived from the International Electrotechnical Commission (IEC) standard 61400-1,the applicability of the methods computing extreme wind load parameters in the IEC standard are investigated under typhoon conditions.The results are as follows.(1) The changes of both the offshore extreme gust wind speeds and the extreme wind directions render a "M" shape bi-modal distribution with peak values in the eyewall region of Hagupit.(2) There are significant differences of amplitudes of the observed extreme operating gust wind speeds and extreme wind direction from the results calculated from the IEC standard.(3) The amplitudes of both the extreme operating gust wind speeds and the extreme directions exceed the upper limits of the IEC standard for three standard classes of wind turbines,and the values calculated by IEC standard are much significantly larger than the measured ones.(4) The observed extreme operating gust wind speeds are consistent with the results calculated by the IEC standard when wind turbines are under full or partial workload or cut-off conditions,although the amplitude of extreme wind directions calculated in terms of the IEC standard is larger than that of direct measurements.Measured extreme operating gust wind speeds sometimes exceed the IEC design criteria.
文摘Article use Visual LISP development tools and DCL dialog technology, which implements the standard straight teeth, a two- dimensional cylindrical gear paranaetric drawing on AutoCAD platform, with easy to operate and improve design efficiency. We achieved that using the dialog box design input parameters, and gear parts of the design calculations, parameters proofreading and all kinds of gear design drawing different structures by programming. The output is fully automated computer-aided design system. The results show that the design of the system significantly improves the efficiency of the part design.
文摘This paper introduces a new study on the optimum calculation of partial transmission ratios of mechanical drive system using a V-belt and two-step bevel helical gearbox for getting minimum size of the system. In the paper, based on moment equilibrium condition of a mechanic system including V-belt and a two-gear-unit of the gearbox, models for optimum calculation of the partial ratios of the V-belt and the gearbox were proposed. As the models are explicit, the partial ratios can be calculated accurately and simply.
文摘This study examines experimentally the effect of stators on the performance and heat transfer characteristics of small axial cooling fans. A single fan impeller, followed by nine stator blades in the case of a complete stage, was used for all the experimental configurations. Performance measurements were carried out in a constant speed stage performance test rig while the transient liquid crystal technique was used for the heat transfer measurements. Full surface heat transfer coefficient distributions were obtained by recording the temperature history of liquid crystals on a target plate. The experimental data indicated that the results are highly affected by the flow conditions at the fan outlet. Stators can be beneficial in terms of pressure drop and efficiency, and thus more economical operation, as well as, in the local heat transfer distribution at the wake of the stator blades if the fan is installed very close to the cooling object. However, as the separation distance increases, enhanced heat transfer rate in the order of 25% is observed in the case of the fan impeller.
