Articles techniques et présentations

Design and manufacture of thrusters for producing very low thrust force in the range of milli or micro newtons using micronozzles has been actively developed in the last decade. The nature of propellant flow in such micronozzles differs from that of macro nozzles. In micronozzles, viscous effect dominates; hence the flow is always in laminar regime with high viscous losses. Objective of this paper is to address these issues in micronozzle flow of vapor and also to compare the performance of two different micronozzle geometries. A numerical study has been carried out on the flow of water as propellant in vapor phase inside a 3D micronozzle. The study involved solving the Navier–Stokes equation with no slip boundary condition and equation of energy conservation. The computational model is validated with available experimental data in the literature. The computations are performed for different mass flow rates with inlet vapor temperature kept constant at 600K. Different output parameters of both nozzle geometries are compared and the boundary layer effects are also quantified.