Performance Modeling of the Phoenix-2A Hybrid Sounding Rocket using the HYROPS Software

Abstract

The University of KwaZulu-Natal's Phoenix Hybrid Sounding Rocket Program aims to develop a hybrid sounding rocket, called Phoenix-2A that is capable of reaching a 100 km apogee with a 5 kg payload. The rocket must be safe, reusable and designed for scientific research. The program has been under way since 2010 with the design and development of Phoenix-1A, a small scale hybrid rocket capable of reaching an altitude of 10 km. Nitrous oxide and Sasol 0907 paraffin wax are the selected propellants for Phoenix-2A. The design phase incorporates the use of a UKZN-developed motor performance and flight dynamics simulation tool, HYROPS (Hybrid Rocket Performance Simulator). The design methodology implemented for the preliminary design is discussed and illustrates the architecture of the HYROPS software. Parametric trade studies have been conducted to determine the sensitivity of varying key propulsion and aerodynamic design parameters. Propulsion parameters included are chamber pressure, O/F ratio, and design atmospheric pressure. These studies act as a platform for the development of large scale hybrid rockets. The structural integrity of large scale fuel grains is also being investigated. NomenclatureA t = nozzle throat area C F = thrust coefficient C * = characteristic velocity F D = design thrust mdot n = nozzle mass flow rate O/F = oxidizer to fuel ratio P atm = atmospheric pressure P c = chamber pressure P e = exit pressure ∆P inj = pressure drop across injector η = combustion efficiency

Explicit Modelling of the Ignition Transient Structural Response of a Paraffin Wax Hybrid Rocket Motor Fuel Grain

“…Design and test data of rocket motors is necessary to evaluate the use of the defined model parameters, and thus the authors based such inputs on design characteristics associated with sounding rockets of the University of KwaZulu-Natal's Phoenix Hybrid Sounding Rocket Program (Balmogim et al 2015;Genevieve et al 2012Genevieve et al , 2015Leverone et al 2013Leverone et al , 2019. These vehicles are at varying stages of development and are designed with a large variety of desired apogees and research outcomes.…”

“…The various geometrical and performance properties of these vehicles were determined using the internally developed Hybrid Rocket Performance Simulator (HYROPS). More information on the design process and the use of HYROPS can be found in the references Balmogim et al (2015), Genevieve et al (2015) and Leverone et al (2013). The ratio of the outer diameter (OD) (b) to the inner diameter (ID) (a) (OD/ID ratio) has been used as a general design rule to reduce internal stresses of the grain as per Fig.…”

“…These scenarios included actual pressure data from available hot-fire tests, the modelled theoretical pressure data based on the HYROPS software estimations (including an estimated pressure spike), and a reduced pressure profile where the chamber pressure does not exceed the design pressure (excluding the pressure spike). All pressure profiles are available in references Balmogim et al (2015), Genevieve et al (2012Genevieve et al ( , 2015 and Leverone et al (2013Leverone et al ( , 2019. It is important to note that the pressure profiles and start-up transients greatly affect the ability of paraffin wax fuel grains to withstand the loads applied, as the material is noticeably strain-rate dependent.…”

“…On the other hand, however, the lower OD/ID ratio should counteract this effect. With the modelled loading condition determined during the design of the P-2A motor (Leverone et al 2013), with no ignition pressure spike, failure was predicted to occur by the associated simulation at 0.0086 s into the start-up transient.…”

“…The propellant combination of interest in this research is SASOL 0907 paraffin wax as fuel with nitrous oxide as the oxidiser. This propellant combination is utilised as the primary propulsion mechanism for the University of KwaZulu-Natal's Phoenix Hybrid Sounding Rocket Program (Balmogim et al 2015;Genevieve et al 2012Genevieve et al , 2015Leverone et al 2013Leverone et al , 2019. Additionally, the Phoenix program plans to utilise aluminium powder additives in the paraffin wax at varying percentages to improve the performance and density specific impulse of the motors (Maharaj et al 2016).…”