Abstract

Here, space electroosmotic thrusters in a rigid nanochannel with high wall zeta potentials are investigated numerically, for the first time, considering the effect of finite size of the ionic species. The effect, which is called a steric effect, is often neglected in research about micro/nano thrusters. However, it has vital influences on the electric potential and flow velocity in electric double layers, so that the thruster performances generated by the fluid motion are further affected. These performances, including thrust, specific impulse, thruster efficiency, and the thrust-to-power ratio, are described by using numerical algorithms, after obtaining the electric potential and velocity distributions under high wall zeta potentials ranging from −25.7 mV to −128.5 mV. As expected, the zeta potential can promote the development of thruster performances so as to satisfy the requirement of space missions. Moreover, for real situation with consideration of the steric effect, the thruster thrust and efficiency significantly decrease to 5–30 micro Newtons and 80–90%, respectively, but the thrust-to-power ratio is opposite, and expends a short specific impulse of about 50–110 s.

Highlights

  • Mala et al [20] investigated the influences of electric double layer (EDL) on electroosmosis flow (EOF) between two parallel plates, experimentally and theoretically

  • Soft nanochannels were further considered by Zheng and Jian [24,25], who obtained up to 90% efficiency, as well as a few micro Newtons of thrust. These works pertaining to electroosmotic thrusters were carried out under the condition of a small electric potential, so, in the present paper, we firstly tried to investigate thruster performances in a rigid nanochannel considering the effects of a high zeta potential on the walls

  • We considered the thruster model problem of electroosmotic-driven flows through a nanochannel with a high wall zeta potentials under the steric effect

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Summary

Introduction

Soft nanochannels were further considered by Zheng and Jian [24,25], who obtained up to 90% efficiency, as well as a few micro Newtons of thrust These works pertaining to electroosmotic thrusters were carried out under the condition of a small electric potential, so, in the present paper, we firstly tried to investigate thruster performances in a rigid nanochannel considering the effects of a high zeta potential on the walls. The influence of the steric effect was first added by Zheng et al [34] in space electroosmotic thrusters with soft nanochannels They found that the thruster efficiency was only 30–70% and the peak values of the thrust-to-power ratio faded away, but they did not consider the high wall zeta potential. Their variations with regard to the zeta potential and the steric factor are discussed in detail

Mathematical Model Analysis
Electric Potential Distribution
Velocity Distribution
Thruster Performance Analysis
Specific Impulse
Thrust
Thruster Efficiency
Thrust-to-Power Ratio
Numerical Algorithm
Results and Discussion
Conclusions
Full Text
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