For a 120 kW hydrogen fuel cell system,a centrifugal air compressor with fixed power of 22 kW fuel cell is designed.Firstly,the theoretical calculation is carried out for the aerodynamic characteristics of a ultra-hig...For a 120 kW hydrogen fuel cell system,a centrifugal air compressor with fixed power of 22 kW fuel cell is designed.Firstly,the theoretical calculation is carried out for the aerodynamic characteristics of a ultra-high-speed permanent magnet synchronous motor,an air compressor,and an aerodynamic foil bearing.Then,a prototype is trial-produced and a related test bench is built for test verification.Finally,both the simulation and test results indicate that the designed centrifugal air compressor meets the overall requirements of the hydrogen fuel cell system,and the relevant conclusions provide both theoretical and experimental references for the subsequent series development and design of the centrifugal air compressor.展开更多
Based on the running characteristics and high energy consumption of air compressors in coal mines,an air pressure PID closed loop control system has been designed in this paper.The system is composed of PLC, converter...Based on the running characteristics and high energy consumption of air compressors in coal mines,an air pressure PID closed loop control system has been designed in this paper.The system is composed of PLC, converter and sensors etc and adopts the control method of converter triple-evaporator which makes air supply"need-based".The designed system has been applied in multiple coal mines and the results show its energy saving is remarkable and potential application is widely.展开更多
The control system takes the outlet pressure of the chiller as the main control object, adopts the sensor technology to collect and monitor the outlet air bag pressure in real time, and automatically completes the pur...The control system takes the outlet pressure of the chiller as the main control object, adopts the sensor technology to collect and monitor the outlet air bag pressure in real time, and automatically completes the purging PID control according to the set value.展开更多
Air compressor is commonly used in petroleum, chemical industry, smelting, mine ventilation and many other important departments. Once the failure occurs, the production will be seriously affected. Taking an air compr...Air compressor is commonly used in petroleum, chemical industry, smelting, mine ventilation and many other important departments. Once the failure occurs, the production will be seriously affected. Taking an air compressor as an example, the reasons for high bearing temperature and the treatment process are expounded, and the measures such as replacing the bearing, repairing the oil sac on the oil return side of the bearing and installing the bearing are put forward. The rotor shaft grounding measuring device is introduced to solve the high temperature problem of generator bearing, which can provide reference experience for dealing with this problem of the same type of unit.展开更多
Due to the lack of proper monitoring during the operation of the air compressor, the change of load is easy to lead to the failure of no-load or light-load operation, which indirectly affects the production. For this ...Due to the lack of proper monitoring during the operation of the air compressor, the change of load is easy to lead to the failure of no-load or light-load operation, which indirectly affects the production. For this reason, we designed a monitoring system for air compressor. The system uses a distributed three-layer structure, namely the ground monitoring management layer, the network transmission layer and the underground field monitoring layer. Besides, the monitoring substation is installed underground to monitor the operation state of the unit. Use compressors in local conditions. The ground provides comprehensive regulation and control to achieve reasonable operation of the air compressor. The system makes the machine run smoothly, reduces the energy consumption, improves the stability and greatly improves the production efficiency.展开更多
Air compressor is an important engineering equipment that is often used. On this basis, we mainly analyze the automatic control technology of air compressor, and introduce and study the actual control effect of air co...Air compressor is an important engineering equipment that is often used. On this basis, we mainly analyze the automatic control technology of air compressor, and introduce and study the actual control effect of air compressor and its monitoring equipment. The related technical characteristics of the machine automatic control system provide the basic automation guarantee for the efficient and reliable operation of the air compressor system.展开更多
The actuality and disadvantages of traditional high power asynchronism motor drive air compressor in locomotive ser-vice plant are discussed. In order to reduce the energy consumption and obtain safe running, a variab...The actuality and disadvantages of traditional high power asynchronism motor drive air compressor in locomotive ser-vice plant are discussed. In order to reduce the energy consumption and obtain safe running, a variable frequency con-trol method to the motor is supplied. A PLC with touch screen is used for monitoring the status of the compressor and its control system. It also presents energy consumption analysis caused by the variable frequency control method in a locomotive service plant.展开更多
Hydraulic Air Compressor (HAC) is a device which converts hydraulic energy to energy of compressed air. A better exploitation of this hydraulic resource is currently investigated. The aim of the current work is to ana...Hydraulic Air Compressor (HAC) is a device which converts hydraulic energy to energy of compressed air. A better exploitation of this hydraulic resource is currently investigated. The aim of the current work is to analyze a low head open type HAC in terms of compression ratio and HAC efficiency. The performance of HAC is both experimentally and theoretically investigated for various air admission system parameters (air tube length and diameter), downcomer length and hydraulic head. The results are both presented and discussed. Variation of the mean diameter of air bubbles in the downward flow in the downcomer is both determined and investigated. The losses in the whole system are classified, investigated and its impact on HAC is discussed.展开更多
This article experimentally studies the effects of air injection near the blade trailing edge on flow separation and losses in a highly loaded linear compressor cascade. Aerodynamic parameters of eight cascades with d...This article experimentally studies the effects of air injection near the blade trailing edge on flow separation and losses in a highly loaded linear compressor cascade. Aerodynamic parameters of eight cascades with different air injection slot configura- tions are measured by using a five-hole probe at the cascade outlets. Ink-trace flow visualization is performed to obtain the flow details around the air injection slots. The static pressure distribution is clarified with pressure taps on the endwalls. The...展开更多
According to the requirements of welding process for vortex type compressor of air conditioner manufactured in product line, a special girth welding machine with PLC as control core was developed, which had both uprig...According to the requirements of welding process for vortex type compressor of air conditioner manufactured in product line, a special girth welding machine with PLC as control core was developed, which had both upright and 45 ° incline service positions. And some key technologies were researched, such as structural design of machine body, reliable conduction of rotary weldments and quality control of welding process and so on. The experimental results showed that this machine could satisfy the requirements of welding quality and girth welding technology, results also proved the machine was a high-effwiency and low-cost automatic welding device.展开更多
Steady air injection upstream of the leading edge was used to increase the surge margin of a centrifugal compressor.To reveal the mechanism,steady numerical simulations were performed on a high pressure ratio centrifu...Steady air injection upstream of the leading edge was used to increase the surge margin of a centrifugal compressor.To reveal the mechanism,steady numerical simulations were performed on a high pressure ratio centrifugal compressor rotor operated with a rotor tip speed of 586 m/s.Eight different injection yaw angle with four different injection mass flow was performed to determine the configuration that provide the best results for the compression system studied in this work.The injection angle,α,was fifteen degree and the injectors were placed at short distance（ten percent of the inlet tip radius upstream of the compressor face） to achieve maximum control over the leading edge flow by varying individual injection parameters.The results show that at design speed（n=50 000 r/min） with injection flow rate more than 2% of the main flow rate and yaw angle between 20° and 30°,the mass flow rate at stall decreases for approximately 8%.But with higher injection rate,other compressor parameters were affected such as compressor efficiency and compressor total pressure ratio.展开更多
A novel variable displacement compressor (VDC) for automotive air conditioner (AAC) is introduced, which inherits the advantages of common wobble plate type VDC. It has fewer parts and makes less noise, and instead of...A novel variable displacement compressor (VDC) for automotive air conditioner (AAC) is introduced, which inherits the advantages of common wobble plate type VDC. It has fewer parts and makes less noise, and instead of pneumatic valve the displacement is controlled by electronic control valve. In order to know the control mechanism well and get a good control effect, a mathematical model for the variable displacement mechanism is developed according to the geometrical and kinematical information of the compressor. Using the model, the effect of relevant parameters on variable displace control is estimated. It is helpful to make the optimum decision in the flow control of AAC. As the novel displacement control device, the structure and control rule of electronic control valve is introduced. It can get better effect than the conventional pneumatic valves. And by using this new electronic control device, the optimum systemic control of AAC is available.展开更多
The inlet-air distortion which was caused by high angle-of-attack flight was simulated by plugboard.Experiments were conducted on a transonic axial-flow compressor's rotor at 98% rotating speed.The flow-field char...The inlet-air distortion which was caused by high angle-of-attack flight was simulated by plugboard.Experiments were conducted on a transonic axial-flow compressor's rotor at 98% rotating speed.The flow-field characteristics and mechanism of performance degradation were analyzed in detail.The compressor inlet was divided into four sectors at circumference under inlet-air distortion.They were undistorted sector,transition sector A where the rotor was rotating into the distortion sector,distorted sector and transition sector B where the rotor was rotating out of the distortion sector.The experimental results show that compared with undistorted sector,there is a subsonic flow in transition sector A,so the pressure ratio is decreased by a large margin in this sector.However,the shock wave is enhanced in distortion sector and transition sector B,and thus the pressure ratio increases in these sectors.Because of the different works at circumference,the phase angle of total pressure changes 90° when the inlet total pressure distortion passes through compressor rotor.In addition,the frequency and amplitude of disturbances in front of the rotor strengthenes under inlet distortion,so the unstable flow would take place in advance.In addition,the position of stall inception is in one of the transition sectors.展开更多
基金supported in part by the Key R&D projects in Hebei Province under Grant 20312202D。
文摘For a 120 kW hydrogen fuel cell system,a centrifugal air compressor with fixed power of 22 kW fuel cell is designed.Firstly,the theoretical calculation is carried out for the aerodynamic characteristics of a ultra-high-speed permanent magnet synchronous motor,an air compressor,and an aerodynamic foil bearing.Then,a prototype is trial-produced and a related test bench is built for test verification.Finally,both the simulation and test results indicate that the designed centrifugal air compressor meets the overall requirements of the hydrogen fuel cell system,and the relevant conclusions provide both theoretical and experimental references for the subsequent series development and design of the centrifugal air compressor.
文摘Based on the running characteristics and high energy consumption of air compressors in coal mines,an air pressure PID closed loop control system has been designed in this paper.The system is composed of PLC, converter and sensors etc and adopts the control method of converter triple-evaporator which makes air supply"need-based".The designed system has been applied in multiple coal mines and the results show its energy saving is remarkable and potential application is widely.
文摘The control system takes the outlet pressure of the chiller as the main control object, adopts the sensor technology to collect and monitor the outlet air bag pressure in real time, and automatically completes the purging PID control according to the set value.
文摘Air compressor is commonly used in petroleum, chemical industry, smelting, mine ventilation and many other important departments. Once the failure occurs, the production will be seriously affected. Taking an air compressor as an example, the reasons for high bearing temperature and the treatment process are expounded, and the measures such as replacing the bearing, repairing the oil sac on the oil return side of the bearing and installing the bearing are put forward. The rotor shaft grounding measuring device is introduced to solve the high temperature problem of generator bearing, which can provide reference experience for dealing with this problem of the same type of unit.
文摘Due to the lack of proper monitoring during the operation of the air compressor, the change of load is easy to lead to the failure of no-load or light-load operation, which indirectly affects the production. For this reason, we designed a monitoring system for air compressor. The system uses a distributed three-layer structure, namely the ground monitoring management layer, the network transmission layer and the underground field monitoring layer. Besides, the monitoring substation is installed underground to monitor the operation state of the unit. Use compressors in local conditions. The ground provides comprehensive regulation and control to achieve reasonable operation of the air compressor. The system makes the machine run smoothly, reduces the energy consumption, improves the stability and greatly improves the production efficiency.
文摘Air compressor is an important engineering equipment that is often used. On this basis, we mainly analyze the automatic control technology of air compressor, and introduce and study the actual control effect of air compressor and its monitoring equipment. The related technical characteristics of the machine automatic control system provide the basic automation guarantee for the efficient and reliable operation of the air compressor system.
文摘The actuality and disadvantages of traditional high power asynchronism motor drive air compressor in locomotive ser-vice plant are discussed. In order to reduce the energy consumption and obtain safe running, a variable frequency con-trol method to the motor is supplied. A PLC with touch screen is used for monitoring the status of the compressor and its control system. It also presents energy consumption analysis caused by the variable frequency control method in a locomotive service plant.
文摘Hydraulic Air Compressor (HAC) is a device which converts hydraulic energy to energy of compressed air. A better exploitation of this hydraulic resource is currently investigated. The aim of the current work is to analyze a low head open type HAC in terms of compression ratio and HAC efficiency. The performance of HAC is both experimentally and theoretically investigated for various air admission system parameters (air tube length and diameter), downcomer length and hydraulic head. The results are both presented and discussed. Variation of the mean diameter of air bubbles in the downward flow in the downcomer is both determined and investigated. The losses in the whole system are classified, investigated and its impact on HAC is discussed.
基金National Natural Science Foundation of China (50876023)Chinese Specialized Research Fund for the Doctoral Pro-gram of Higher Education (20060213007)National Basic Research Program of China (2007CB210100)
文摘This article experimentally studies the effects of air injection near the blade trailing edge on flow separation and losses in a highly loaded linear compressor cascade. Aerodynamic parameters of eight cascades with different air injection slot configura- tions are measured by using a five-hole probe at the cascade outlets. Ink-trace flow visualization is performed to obtain the flow details around the air injection slots. The static pressure distribution is clarified with pressure taps on the endwalls. The...
文摘According to the requirements of welding process for vortex type compressor of air conditioner manufactured in product line, a special girth welding machine with PLC as control core was developed, which had both upright and 45 ° incline service positions. And some key technologies were researched, such as structural design of machine body, reliable conduction of rotary weldments and quality control of welding process and so on. The experimental results showed that this machine could satisfy the requirements of welding quality and girth welding technology, results also proved the machine was a high-effwiency and low-cost automatic welding device.
基金Supported by Chinese Specialized Research Fund for the Doctoral Program of Higher Education (20091101110014)the National Natural Science Foundation of China (51176013)National High Technology Research and Development Program of China("863" Program) (2007AA050502)
文摘Steady air injection upstream of the leading edge was used to increase the surge margin of a centrifugal compressor.To reveal the mechanism,steady numerical simulations were performed on a high pressure ratio centrifugal compressor rotor operated with a rotor tip speed of 586 m/s.Eight different injection yaw angle with four different injection mass flow was performed to determine the configuration that provide the best results for the compression system studied in this work.The injection angle,α,was fifteen degree and the injectors were placed at short distance（ten percent of the inlet tip radius upstream of the compressor face） to achieve maximum control over the leading edge flow by varying individual injection parameters.The results show that at design speed（n=50 000 r/min） with injection flow rate more than 2% of the main flow rate and yaw angle between 20° and 30°,the mass flow rate at stall decreases for approximately 8%.But with higher injection rate,other compressor parameters were affected such as compressor efficiency and compressor total pressure ratio.
文摘A novel variable displacement compressor (VDC) for automotive air conditioner (AAC) is introduced, which inherits the advantages of common wobble plate type VDC. It has fewer parts and makes less noise, and instead of pneumatic valve the displacement is controlled by electronic control valve. In order to know the control mechanism well and get a good control effect, a mathematical model for the variable displacement mechanism is developed according to the geometrical and kinematical information of the compressor. Using the model, the effect of relevant parameters on variable displace control is estimated. It is helpful to make the optimum decision in the flow control of AAC. As the novel displacement control device, the structure and control rule of electronic control valve is introduced. It can get better effect than the conventional pneumatic valves. And by using this new electronic control device, the optimum systemic control of AAC is available.
基金National Natural Science Foundation of China(50906001)
文摘The inlet-air distortion which was caused by high angle-of-attack flight was simulated by plugboard.Experiments were conducted on a transonic axial-flow compressor's rotor at 98% rotating speed.The flow-field characteristics and mechanism of performance degradation were analyzed in detail.The compressor inlet was divided into four sectors at circumference under inlet-air distortion.They were undistorted sector,transition sector A where the rotor was rotating into the distortion sector,distorted sector and transition sector B where the rotor was rotating out of the distortion sector.The experimental results show that compared with undistorted sector,there is a subsonic flow in transition sector A,so the pressure ratio is decreased by a large margin in this sector.However,the shock wave is enhanced in distortion sector and transition sector B,and thus the pressure ratio increases in these sectors.Because of the different works at circumference,the phase angle of total pressure changes 90° when the inlet total pressure distortion passes through compressor rotor.In addition,the frequency and amplitude of disturbances in front of the rotor strengthenes under inlet distortion,so the unstable flow would take place in advance.In addition,the position of stall inception is in one of the transition sectors.
