Year: 2018
Type: dissertation
Abstract: The deployment of micro- and nanosatellites has greatly increased over the past few decades with \nadvances in miniaturized electronics for communication, imaging and attitude control. The South \nAfrican satellite industry is now also currently developing two microsatellites and nanosatellites \nfor launch by foreign providers. The outsourcing of launch services to foreign providers is costly \nand can lead to unanticipated delays. In this context, the UKZN Aerospace Systems Research \nGroup (ASReG), in conjunction with the Council for Scientific and Industrial Research (CSIR) \nhas begun designing a modular and compact liquid propulsion engine (LOX/RP-1) named \nSAFFIRE (South AFrican First Integrated Rocket Engine). \nThis dissertation details the design and analysis of the liquid oxygen pump that delivers the \noxidiser to the SAFFIRE combustion chamber at high pressure, where the propellants are burnt \nand expelled, generating thrust. The pump is electrically powered as opposed to the conventional \nturbine-driven turbopump, to further simplify start-stop procedures and reduce the complexity of \nthe engine. The pump’s operating conditions were determined by an engine performance analysis, \nwith these results forming the initial conditions for the pump design process. The oxidiser pump \nis required to deliver a mass flow rate of 6.13 kg/s at a pressure of 62.8 bar. The pump was designed using conventional centrifugal pump design procedures, with special \nconsiderations taken due to the working temperature of liquid oxygen being -183°C. The final \none-dimensional design for the impeller was developed using the commercial software \nPUMPAL™, which was provided by the CSIR. A 3D impeller geometry was developed by \nimporting the one-dimensional design into AxCent™, where quasi-3D Multiple Stream Tube \n(MST) analysis and full 3D computational fluid dynamics (CFD) simulations were performed. \nThe impeller design was refined multiple times until the parameters set by the engine performance \nanalysis were met. The AxCent™ analyses determined that low-pressure zones occurred at the \ninlet of the pump impeller. Hence Star-CCM+™, which has a more robust computational solver \nand allows for a full transient, multiphase CFD to be performed, was employed to analyse any \npotential cavitation affects. The results from Star-CCM+™ and AxCent™ were compared and \ndesigns altered until a final design was realized that met the prescribed performance parameters. \nThe final pump impeller has an outer diameter of 86 mm, delivering a mass flow rate of 6.13 kg/s \nat a pressure of 64.2 bar. The pump operates at an efficiency of 60.8% requiring a power input of \n51.96 kW at a rotational speed of 26000 rpm.
Author: Nalendran. Singh
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
Funder: Inyuvesi Yakwazulu-Natali
OpenAlex ID: W2931839796