Estimation of the mass of the centrifugal electric pump unit of the spacecraft thermal control system

Abstract

The article deals with the problem of estimating the mass of a centrifugal electric pump unit of a spacecraft thermal control system at the stage of preliminary design. The energy parameters of the electric pump are considered as the initial information relevant for the specified assessment: mass and volume flow V(m3/sec), head H (Joule/kg) and speed factor ns (dimensionless parameter). Based on the known data, using a third-order equation, an approximation of the graphical dependence of the reduced mass Mm of aggregates on the mass flow rate of the coolant (kg/sec) was carried out. An analysis of the equation showed that starting from the value m =0.15 kg/sec, the dependence becomes asymptotic, indicating the invariance of the reduced mass of the unit with a further increase in flow. The obtained dependence, covering a narrow range of variation, does not allow us to evaluate the changes of the reduced mass of the unit when designing a unified series of designs of the centrifugal electric pump unit of the spacecraft thermal control system, taking into account changes in such energy parameters as head, volume flow and speed coefficient. Therefore, at the 2nd stage of the study, an analysis of the influence of these parameters was carried out within the framework of the graph V = f (H), containing the level lines ns = const and Mm = const. It follows from the graph that if the increase in pressure H is due to an increase in the number of revolutions of the rotor, then such a modification of the unit is not accompanied by an increase in the radial dimensions and absolute mass of the design of the centrifugal electric pump unit.