Effects of Catalyst Bed Failure on Thermochemical Phenomena for a Hydrazine Monopropellant Thruster Using Ir/Al₂O₃ Catalysts

Abstract

Hydrazine monopropellant has been used in thrusters for maneuvering satellites and landing spacecraft. Testing and handling procedures for hydrazine monopropellant thrusters are complicated, because of the toxicity of the hydrazine and its decomposition product gases. Therefore, simulated numerical analysis can help elucidate the effects of various thruster design parameters and can reduce both development time and expenses. In this study, a simulated numerical analysis was performed in which the catalyst bed was modeled as a one-dimensional porous medium. The resulting physical phenomena were examined by considering variations in catalyst bed characteristics incurred by catalyst pellet failure. From observations of various hot-firing experiments, it was determined that the upper region of the decomposition chamber was preferentially damaged in failure situations, which led to the conclusion that catalyst failure occurs in the upper region only. We simulated various cases based on the crushing and mass loss of catalyst pellets. The distributions of temperature, species mass fraction, heterogeneous reaction rate, and pressure were calculated after catalyst bed failure. The pressures at the decomposition chamber exit and the thrust at the nozzle exit were monitored with time. Through these analyses, the thermochemical phenomena inside a hydrazine monopropellant thruster system were interpreted in detail.

Development of novel supported iridium nanocatalysts for special catalytic beds

“…NH 3 and N 2 are major gases when the temperature is low with slight H 2 selectivity [25]. The reaction can be described in two steps [26]:…”

A kriging based multi objective gray wolf optimization for hydrazine catalyst bed

“…These thrusters use catalytic decomposition to change the propellants chemical energy to thermal energy (Larson et al 1995;Sutton & Biblarz, 2010). Although Hydrazine (Adami et al, 2015a;Jung et al, 2013;Rath et al, 1996;Schmuland et al, 2011), hydrogen peroxide (Adami et al, 2015b;Amrousse et al, 2011;Rhee et al, 2000;Pasini et al, 2011;Whitehead, 1998), Hydroxyl Ammonium Nitrate (HAN) (Chen et al, 2016), De-Methyl Amino Ethyl Aside, hydrazinium nitro formate (HNF) and Nitro oxide (Lohner et al , 2008) are proposed as liquid monopropellant; hydrazine has received a great deal of attention for many years for space applications that require very high reliability (Hwang et al, 2012).…”

“…Except the catalyst bed the other ones are the same mono and bipropellant motor, so it's the most important element of a monopropellant thruster system. In the other hand as the catalyst bed controls propellant decomposition, which determines the overall thruster performance, the importance of this item heightens (Hwang et al, 2012). Transition metal and their derivatives have excellent catalytic behavior (Chen et al, 2002).…”

Ir Impregnation on Alumina Pores: Catalyst Activity and Loss During Hydrazine Decomposition

“…Many investigations have focused on the decomposition of hydrazine over Ir/γ-Al 2 O 3 catalysts [21][22][23][24][25][26][27][28] suggesting that it is the most attractive catalyst choice for hydrazine decomposition in space thruster applications. Some ambi-guities, however, still remain due to the complex phenomena occurring during the reaction within the catalyst pellets.…”