A new method of electrical discharge machining （EDM） in air-mixed medium--air-mixed EDM was presented, and comparative experiments were carried out to compare the machining characteristics of air-mixed EDM with conv...A new method of electrical discharge machining （EDM） in air-mixed medium--air-mixed EDM was presented, and comparative experiments were carried out to compare the machining characteristics of air-mixed EDM with conventional EDM. The experimental results showed that better machining performances were obtained with tool electrode as the cathode and workpieee as the anode. It was found that the material removal rate （MRR） was higher, the tool electrode relative wear ratio （TWR） was lower and the surface roughness （SR） quality was better in the case of air-mixed EDM than that of conventional EDM, and the reasons bringing out the results were analyzed.展开更多
A design of the high-current modular pulsed power generator and results of the test of this generator are presented. The generator is based on two capacitors each of 2.5μF and 50 kV maximum charging voltage. Two mult...A design of the high-current modular pulsed power generator and results of the test of this generator are presented. The generator is based on two capacitors each of 2.5μF and 50 kV maximum charging voltage. Two multi-gaps gas spark switches with capacitive coupled triggering are used to discharge stored energy into the load. The triggering pulse with amplitude up to 70 kV and rise time of-50 ns is supplied by three-stage Marx-generator. The output of each capacitor with multi-gaps spark switch is connected to the load by eight coaxial cables -1 m in length. The total inductance of the generator does not exceed 200 nil. At 40 kV charging voltage this generator produces 180 kA with a quarter of period of 1.6 μs at short circuit load of-15 nil. The generator has been used in the research of underwater electrical wire explosion. The space separation of the load and modules of generator allows one to avoid possible damages of the generator by shock waves produced during the wire explosion. In addition, this modular generator design allows to increase easily the number of modules and to reach several hundreds of kiloamperes in the load.展开更多
In this paper the main technical data of the high speed camera(HSFC-PRO),components of gas triggered switch and the primary experimental results of the breakdown of gas triggered switch using high speed camera are int...In this paper the main technical data of the high speed camera(HSFC-PRO),components of gas triggered switch and the primary experimental results of the breakdown of gas triggered switch using high speed camera are introduced.Four photographs totaling in 24 nanoseconds in single trigger mode manifest that the breakdown consists of two phases,which are the breakdowns of the trigger electrode with positive and negative electrode successively. This phenomenon is consist with the electric field distribution simulation result with the help of the software ANSYS. Eight photographs in double trigger mode prove that the breakdown time of the gas triggered switch is above 10.5 microseconds.The elementary results show that high speed camera is a very efficient apparatus to study the discharge characteristics.This optical measuring technique is helpful to profoundly study the breakdown of high voltage switch. More studies and experiments would be continued in future.展开更多
In this study, an electro-mechanical valve （EMV） system for the intake valve ofa fottr stroke, single cylinder, overhead valve and spark ignition （SI） engine was designed and constructed. An engine with the EMV sy...In this study, an electro-mechanical valve （EMV） system for the intake valve ofa fottr stroke, single cylinder, overhead valve and spark ignition （SI） engine was designed and constructed. An engine with the EMV system and a standard engine were tested to observe the effects of the EMV on engine performance and emissions at different speeds under full load. The EMV engine showed improved engine power, engine torque and break specific fuel consumption （BSFC）. A 66% decrease in CO emissions was also obtained with the EMV system, but hydrocarbons （HC） and NOx emissions increased by 12% and 13% respectively.展开更多
基金the Post-doctor Foundation of Heilongjiang Province(Grant No.LBH-Z06139).
文摘A new method of electrical discharge machining （EDM） in air-mixed medium--air-mixed EDM was presented, and comparative experiments were carried out to compare the machining characteristics of air-mixed EDM with conventional EDM. The experimental results showed that better machining performances were obtained with tool electrode as the cathode and workpieee as the anode. It was found that the material removal rate （MRR） was higher, the tool electrode relative wear ratio （TWR） was lower and the surface roughness （SR） quality was better in the case of air-mixed EDM than that of conventional EDM, and the reasons bringing out the results were analyzed.
文摘A design of the high-current modular pulsed power generator and results of the test of this generator are presented. The generator is based on two capacitors each of 2.5μF and 50 kV maximum charging voltage. Two multi-gaps gas spark switches with capacitive coupled triggering are used to discharge stored energy into the load. The triggering pulse with amplitude up to 70 kV and rise time of-50 ns is supplied by three-stage Marx-generator. The output of each capacitor with multi-gaps spark switch is connected to the load by eight coaxial cables -1 m in length. The total inductance of the generator does not exceed 200 nil. At 40 kV charging voltage this generator produces 180 kA with a quarter of period of 1.6 μs at short circuit load of-15 nil. The generator has been used in the research of underwater electrical wire explosion. The space separation of the load and modules of generator allows one to avoid possible damages of the generator by shock waves produced during the wire explosion. In addition, this modular generator design allows to increase easily the number of modules and to reach several hundreds of kiloamperes in the load.
文摘In this paper the main technical data of the high speed camera(HSFC-PRO),components of gas triggered switch and the primary experimental results of the breakdown of gas triggered switch using high speed camera are introduced.Four photographs totaling in 24 nanoseconds in single trigger mode manifest that the breakdown consists of two phases,which are the breakdowns of the trigger electrode with positive and negative electrode successively. This phenomenon is consist with the electric field distribution simulation result with the help of the software ANSYS. Eight photographs in double trigger mode prove that the breakdown time of the gas triggered switch is above 10.5 microseconds.The elementary results show that high speed camera is a very efficient apparatus to study the discharge characteristics.This optical measuring technique is helpful to profoundly study the breakdown of high voltage switch. More studies and experiments would be continued in future.
基金Project supported by T.R.Prime Ministry State Planning Organization,Turkey
文摘In this study, an electro-mechanical valve （EMV） system for the intake valve ofa fottr stroke, single cylinder, overhead valve and spark ignition （SI） engine was designed and constructed. An engine with the EMV system and a standard engine were tested to observe the effects of the EMV on engine performance and emissions at different speeds under full load. The EMV engine showed improved engine power, engine torque and break specific fuel consumption （BSFC）. A 66% decrease in CO emissions was also obtained with the EMV system, but hydrocarbons （HC） and NOx emissions increased by 12% and 13% respectively.
