Dynamical Model of Rocket Propellant Loading with Liquid Hydrogen

Temperature Stratification in a Cryogenic Fuel Tank

“…Analysis has been performed for both the nominal regime and the effects of several primary faults, such as gas leaks in the ullage space of both the ST and ET, as well as clogging of the ET vent valve on the history of both tanks [1,2]. It is found that each of the faults is characterized by quite a pronounced dynamics.…”

“…Yet, the dynamics of the ET vent valve switching that causes pressure oscillations are shown to be extremely sensitive even to small deviations from the nominal regime and can be used for early fault identification by means of real time sensor data analysis. (The valve in question works between two threshold positions in order to maintain a required ullage pressure [1].) It means that one can not only detect, isolate and identify different faults based on the analysis of the sensor data characterizing the filling dynamics, but also infer the parameters of the model to be further used for prediction of future behavior of the system [2].…”

“…However, the above model, allowing for a fairly adequate description of the ET ullage history [1,2], does not account for a substantial temperature stratification that may happen [3][4][5][6] in both the ullage [7][8][9][10] and the liquid [9,10] control volumes of the external and storage cryogenic tanks. The major goal of the present paper is to develop a model that correctly describes possible thermal stratification in both the ullage and liquid bulk parts of a tank that is based on ordinary differential equations, similar to those discussed in [1], short of a fullscale computational fluid dynamics (CFD) modeling scheme [3][4][5][6][7][8], so that it can be implemented efficiently and used for online state estimation, fault diagnosis, and fault prognosis.…”

“…Recently, a dynamical model was developed for a complex spatially-distributed system of liquid hydrogen (LH2) loading that involves the storage (ST) and external (ET) tanks as well as the transfer line [1]. This reduced model is based on a set of coupled ordinary integro-differential equations, which is shown to be well-suited to describing a generic cryogenic loading system, including one used for Space Shuttle fueling in both the nominal and major faulty regimes.…”

“…The major goal of the present paper is to develop a model that correctly describes possible thermal stratification in both the ullage and liquid bulk parts of a tank that is based on ordinary differential equations, similar to those discussed in [1], short of a fullscale computational fluid dynamics (CFD) modeling scheme [3][4][5][6][7][8], so that it can be implemented efficiently and used for online state estimation, fault diagnosis, and fault prognosis. A distinctive feature of this model is that it takes into consideration non-equilibrium mass and energy exchange processes of condensationevaporation at the liquid-vapor interface between the liquid and gas, and the thermal convection in both the liquid and vapor parts of the tank, which is driven by complex phenomena developing in the boundary layers adjacent to the tank walls as well as to the liquid-vapor interface.…”