Mathematical modelling and numerical simulation of a two-phase heat transport system condenser

The mathematical modelling and numerical simulation of a condenser is discussed. This mathematical model is part of the NLR approach to model and scale two-phase heat transport systems (for space). During a previous study the condensation length required for various gravity conditions, and working fluids has been investigated by means of...

Test loops for two-phase thermal management system components

Two mechanically pumped two-phase test rigs were built at NLR in order to experimentally study critical issues of spacecraft two-phase thermal management systems: - a 5 kW, 31 mm ID, freon loop, focusing on the critical components of the ESA Two-Phase Heat Transport System. - a 30000 W, 4.93 mm ID, ammonia loop, to support the development of the...

Development of a sensor for high-quality two-phase flow

The monitoring of the quality of the two-phase mixture at various locations in the system is a valuable, possibly indispensable, part of the control system needed to properly operate a two-phase heat transport system for large spacecraft. Based on a trade-off of various quality monitoring concepts, NLR started to develop a dedicated quality...

Preliminary experiments with an electro-osmotic heat pipe laboratory model

Preliminary experiments have been performed with a laboratory model of an electro-osmotic heat pipe filled with ethanol. With dismounted electro-osmotic pump, the heat transport through the pipe and the temperature distribution along the pipe wall have been measured. The measurements have been performed as a function of the temperature...

Uniaxial model for a gas loaded variable conductance heat pipe

A new uniaxial model for a gas loaded variable conductance heat pipe (VCHP) is developed. This model takes into account the diffusion at the vapour-gas interface as well as the inertial effects of the moving vapour. Only steady-state conditions are considered. The generally accepted Edwards /Marcus model will be shown to be a first order...

Theory and design of conventional heat pipes for space applications

The scope of this report is: - to give a short description of the possible operation principles and applications of heat pipes - to derive the governing equations for a model of a conventional heat pipe (including the limits to the heat transfer capability) - to describe the theoretical derivation of the formulae for the various thermal...

A theoretical investigation of gas conduction effects on multilayer insulation performance

The thermal performance of multilayer insulation hlankets depends on three (interacting) modes of energy transfer: radiation between the radiation shields, gas conduction in the residual interstitial gas and solid conduction via the contacting interfaces. The contribution of the gas conduction depends on the interstitial gas and its pressure,...