Thermal Modeling Issues Concerning the Mechanically Pumped Two-Phase CO2 Cooling for the AMS-2 Tracker

Abstract

This paper discusses the thermal modeling activities as a design and development tool for the Tracker Thermal Control System, the mechanically pumped, carbon dioxide thermal management system for the AMS-2 Silicon Tracker. Main modeling topics are: radiator sizing and condenser development, set-point control and pre-heating issues with respect to the spatial and temporal temperature gradient requirements of the Tracker.

Development of a Mechanically Pumped Two-Phase CO2 Cooling Loop for the AMS-2 Tracker Experiment

“…More experiments were done at NIKHEF [4] to confirm this in a closed loop set-up ( Fig. 7), which more realistically simulates the TTCS.…”

“…An open test set-up [4], built at NIKHEF in order to prove the feasibility of the TTCS evaporator concept for CO 2 , consisted of an evaporator section connected to a liquid CO 2 filled bottle. The CO 2 flow was adjusted by a needle valve, the pressure in the test tube by a spring-relieve valve (at the exit).…”

“…In addition it is remarked that [4]: -The basic difference between mechanically pumped single-phase (caloric heat transport by the liquid) and two-phase systems (transport by latent heat of evaporation/condensation). This implies for dissipating stations in series in a single-phase system a temperature increase in the downstream direction of the loop.…”

“…Currently the model is being refined and more accurate environmental loading conditions are expected to be provided by the "AMS Overall Thermal" main contractor. Using these new boundary conditions, new calculation runs will be carried out, but only after integrating useful data obtained from the full-size test rig experiments [11].…”

Tutorial on Quantification of Differences between Single- and Two-Component Two-Phase Flow and Heat Transfer

“…Two very important European near-future mechanically pumped two-phase heat transport system applications are: -The two-phase ammonia thermal control system of the Russian segment of the International Space Station, ISS (Grigoriev et al, 1999;Cykhotsky, 1998;Leontiev, 1997). -The hybrid two-phase carbon dioxide thermal control loop of the AMS-2 Tracker Thermal Control System (Delil, 2002a,b,c,d;Woering et al, 2002). AMS-2, the Alpha Magnetic Spectrometer experiment (Viertel, 1999) planned for a five years mission as attached payload on ISS, is an international experiment searching for antimatter, dark and missing matter.…”