Momentum Transfer to Nanoobjects between Parallel Heated Plates

TL;DR

This paper derives an analytical expression and performs simulations to show that a temperature gradient between parallel heated plates can induce a significant force on a nanoobject, useful for nanomachine energy conversion.

Contribution

It introduces an analytical model and validates it with simulations to demonstrate thermally induced forces on nanoobjects in rarefied gas flows.

Findings

Temperature gradient induces a significant force on nanoobjects.

Analytical and Monte-Carlo results are in excellent agreement.

Force persists with only slight reduction at Knudsen number of one.

Abstract

A small-scale, trapezoidal rigid body in the gas-filled gap between two parallel plates at different temperatures is considered. An analytical expression for the force onto the body in the direction parallel to the plates valid for an infinite Knudsen number is derived. Simultaneously, Monte-Carlo simulations are performed allowing to extend the analysis to Knudsen numbers of the order of one. The numerical and the analytical results show excellent agreement, indicating that a temperature gradient orthogonal to the plates can induce a significant force in parallel direction. This force is only slightly reduced when a Knudsen number of one is considered. In the future, the discovered effect may be exploited for the conversion of thermal into mechanical energy in nanomachines.