Air Flow Measurement Techniques Used for International Space Station Node 1 and Laboratory Module Flow Balance Test

The International Space Station Alpha (ISSA) Temperature and Humidity Control (THC) subsystem has been reconfigured and tested for both Node 1 and US Laboratory modules. Each element shares conditioned air that originates in the Lab module and is distributed into either the Lab, Node 1, Mini-Pressurized Logistics Module (MPLM), or the Cupola. This “parasitic” cooling scheme was tested at the McDonnell Douglas Space System Laboratory in Huntington Beach, California, during the summer of 1995. This test involved the use of standard and nonstandard techniques of measuring air flow through a complex system of ducting. Flow balancing was achieved through a series of additional dampers and orifices throughout the system. The purpose of this paper is to review some of the air flow measurement techniques and compare some of the test results with traditional theory. Techniques used for flow balancing, and test conclusions and recommendations, are also included.