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A SINDA/FLUINT analysis of the 2R mission will be presented. The analysis will predict the air temperature, humidity, oxygen, and carbondioxide levels associated with initial permanent habitation of the International Space Station. The Expedition 1 crew will assemble several key Environmental Control and Life Support system components; namely the Vozdukh, Elektron, and Service Module air conditioner. The pre-flight analysis will be compared to actual flight data to validate assumptions and fidelity of the SINDA/FLUINT model. Differences will be evaluated to determine the cause, whether due to modeling deficiencies or invalid assumptions regarding timelined activities.

This paper describes the development of a mechanistic thermo-hydraulic math model of the Pump Module Assembly (PMA) for use onboard Space Station Freedom. The PMA consists of the Rotary Fluid Management Device (RFMD), the Back Pressure Regulating Valve (BPRV), a bellows accumulator, and miscellaneous plumbing. The PMA components act to provide fluid pumping power, control system pressure, and control system fluid inventory. The Central Thermal Bus (CTB) is the primary method of transporting the waste energy generated by the station electrical loads from the acquisition point to final rejection to space. Since the CTB is a two-phase system, control of the operating pressure controls the operating temperature, and defines the heat rejection temperature of the station components. Accurate modeling of the dynamics of the PMA is critical to providing predictions of station thermal performance.

This paper describes the development of a Back Pressure Regulating Valve (BPRV) model for thermal-hydraulic performance analysis of the Space Station Freedom (SSF) Central Thermal Bus (CTB). The CTB is a two-phase ammonia system which transports waste energy generated by station electrical loads to final rejection to space. The BPRV controls the operating temperature of the CTB by controlling the system pressure. The BPRV operates to maintain the CTB system pressure at a prescribed setpoint using a spring-biased mechanism which adjusts the valve area based on the system pressure. The setpoint is changed by varying the load on a control spring. The BPRV model accounts for the mechanical response of the BPRV in transient thermal-hydraulic analysis of the CTB. The model uses force balances to simulate the actions of the valve components in order to calculate the flow area. Transient responses are provided.