2023, 44(10): 1213-1225.
doi: 10.21656/1000-0887.430346
Abstract:
Electroosmotic micro thrusters filled with Phan-Thien-Tanner (PTT) viscoelastic fluid between 2 parallel plates were investigated at high wall zeta potential. The nonlinear Poisson-Boltzmann equation was solved without the Debye-Hückel linear approximation, to obtain the analytical electric potential at the high zeta potential. The numerical velocity of the micro thruster was given under the Navier slip condition in solution of the Cauchy momentum equation satisfied by the PTT fluid. Performances of the micro thrusters, including the specific impulse, the thrust, the efficiency, and the thrust-to-power ratio, were obtained through numerical integration. Finally, effects of the viscoelastic parameters, the wall zeta potential, the slip coefficient, and the double electric layer thickness on the velocity distributions and propeller performances, were discussed. The results show that, compared with the Newtonian fluid, the PTT fluid as a propellant is conducive to the improvement of propeller performances. For example, the fluid velocity increases with the viscoelastic parameters, resulting in an increasing trend of propeller performances. The present thruster delivers a thrust about 0~250 μN with a specific impulse of 800~1 000 ms, achieving an efficiency of 6%~12% and a thrust-power ratio of 0~20 mN/W.
