Kang Xiaoming

Experimental study of an electrostatic field–induced electrolyte jet electrical discharge machining process

In this study, a new electrostatic field–induced electrolyte jet electrical discharge machining method has been proposed, which can automatically generate the tool electrode. Then, a series of experiments have been carried out to reveal the machining mechanism and test the machining ability of this method. The continuous observation experiments and the online current detection experiments have demonstrated that the electrolyte jet discharge machining is a pulsing, dynamic and cyclic process. Moreover, the 20-min time long reverse polarity experiments on the silicon surface have revealed that the machining is an electrical discharge machining process during the negative polarity machining; however, in the positive polarity machining, it is a hybrid electrical discharge machining and electrochemical machining process. Furthermore, the craters as small as 2 µm in diameter on stainless steel and silicon are produced by this electrolyte jet electrical discharge machining, which has proved the micro-machining ability of this method.

Minimum emission current of indium‐field emission electric propulsion thruster

– Field emission electric propulsion (FEEP) thruster is a type of electric propulsion based on space‐proven indium liquid metal ion sources. The lifetime of FEEP thruster limits its application in space. A better method to improve its lifetime is the reduction of emission current. This paper aims to discuss the minimum emission current of operating FEEP thrusters., – In this work, theoretical models, including fluid‐flow model and ion formation model, are analyzed. Current densities of these models are discussed and the minimum emission current is calculated., – There are few equilibrium states under low emission current conditions. However, the minimum emission current is the only stable state at which the FEEP thruster can operate., – This analysis is mainly based on the needle indium FEEP, which is compared indirectly with experiments of gallium., – This paper attempts to help designers choose appropriate electric parameters to improve the lifetime of FEEP., – By introducing and analyzing theoretical models, this paper calculates the minimum emission current for stable operation of FEEP.

A study on the efficiency of pulsed plasma thruster (PPT)

Purpose – The pulsed plasma thruster (PPT) is one sort of promising electric thrusters, but the low efficiency is always a big problem for PPT. Many researches have been working on solving this problem. However, there is still no significant breakthrough. This paper aimed to discuss some methods for improving the PPTs efficiency.Design/methodology/approach – The causes for the low efficiency by analyzing the theoretical models of PPT are discussed, and the influences on PPTs performance investigated in terms of the structural or electrical parameters.Findings – The change of structural or electrical parameters which influence the thrust efficiency significantly are taken into account. In the process of designing PPT, optimized structural and electrical parameters should be chosen to attain a better performance.Research limitations/implications – This analysis is mainly based on the parallel‐rail PPT.Practical implications – The result of analysis is adopted, the higher thrust efficiency of PPT is expect...