Modelling of friction and wear for designing cryogenic valves

From a tribological point of view, the selection of materials for seals for valves of cryogenic rocket engines is a critical issue for the designer. D ue to the lack of comprehensive information on this topic. data have been o btained in the framework of research programmes. In the first step, two polymers potentially usable for sealing cryogenic fl uids were identified, They were submitted to general test conditions to gai n some fundamental understanding of their tribological behaviour when immer sed in a cryogenic fluid. This fundamental understanding proved to be helpf ul for an efficient technical approach. This approach with the test conditions as close as possible to those met in real valves has been used in the second step. In order to obtain the best information with the minimum number of tests, the statistical method of Doe hlert has been adopted. The use of such a method led to the construction of surface response for modelling friction and wear. These surfaces and their associated equation are directly and easily usable by the designer, This w ay of treating technical tribological problem is illustrated by an example. (C) 2001 Elsevier Science Ltd. All rights reserved.