AVS 47th International Symposium
    Vacuum Technology Wednesday Sessions
       Session VT-WeP

Paper VT-WeP16
DSMC Study of Plume Flows in Cryogenic Vacuum Facility

Wednesday, October 4, 2000, 11:00 am, Room Exhibit Hall C & D

Session: Poster Session
Presenter: M.S. Ivanov, Institute of Theoretical and Applied Mechanics, Russia
Authors: M.S. Ivanov, Institute of Theoretical and Applied Mechanics, Russia
G.N. Markelov, Institute of Theoretical and Applied Mechanics, Russia
Correspondent: Click to Email
The study of plume flows has been an interesting research subject area of rarefied gas dynamics in the past. Experimental techniques and various engineering approaches were mainly employed for such studies. The recent resurgence of interest in the subject is prompted by the design of a new generation of satellites and space stations for which an accurate prediction not only of force and heat loads produced by the plumes, but also of contamination is needed. Therefore, a comprehensive study of plume structure including core flow, periphery flow and backflow is very important. For correct simulation of small thruster plumes in experimental facilities, it is necessary to have reasonable low background pressure levels. Main feature of new high vacuum plume test facilities STG (DLR) and CHAFF-IV (USC) is a novel cryogenic array, where the expanding plume gas hits a complex-structured cryosurface and freezes immediately. Nevertheless, disturbance of the plume is possible due to the penetration of condensate vapor and of plume molecules that do not stick immediately to the condensate. Therefore, it is necessary to supplement experimental modeling of plume flows by numerical simulation of the plume flow inside the facility taking into account the influence of incomplete condensation of plume molecules. It will allow one to determine a region where a plume flow is undisturbed as in space for different thruster and facility operating conditions. The main objective of the paper is a numerical study of thruster plume flows under low-density conditions in a cryogenic vacuum facility with consideration of background pressure caused by incomplete condensation of plume molecules on the cryogenic array.