burning wax; a life gb b story - technion...hybrid rockets combusting paraffin wax with gaseous...

Conclusions

Matt Nurick, Aviel Ratson and Rona Razel

Supervisors: Daniel Komornik, Ph.D. Candidate and Prof. Alon Gany

Faculty of Aerospace Engineering – Technion, Israel, July-August 2018

AcknowledgmentsWe would like to thank Daniel Komornik, PhD Candidate, Prof. Alon Gany, andProf. Benveniste (Benny) Natan for hosting and guiding us through our researchin their laboratory. We would also like to thank the foundations and donors fortheir generous support of the SciTech program.

References1. Altman, D. and Holzman, A., "Overview and History of Hybrid RocketPropulsion", in: Fundamentals of Hybrid Rocket Combustion and Propulsion,Progress in Astronautics and Aeronautics, Vol. 218, AIAA, pp. 1-36, 2007.

Results

ExperimentalTests

Fig. 2 – Experimental set-up

The preparation for the experiments includedcasting 17 fuel grain molds and pouring melted waxinside of it to solidify (Fig 1). Figure 1 also presentsa fuel grain before and after firing. Figure 2 displaysa layout of the experimental setup.

Video andCalculator AppOn the website you can view the videosof our firing tests as well as our appwhich calculates essential values thatare required for testing.

Use the QR code or visit:

goo.gl/R8wCUq

A hybrid rocket is a motor that combinesfuel in a solid state and oxidizer in agaseous or liquid state. These rocketsexhibit unique advantages, such asimproved safety.

Fig. 3 displays a static firing test. Data revealed a significantly differentregression rate between the hot and cold engines (Fig. 4). This is alogical result as cold engines require more thermal energy toevaporate the wax. However, the difference in performance wasnegligible (Fig. 5). Therefore rockets can be used in various locationsacross the globe without its performance being affected by theregion’s climate.

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Introduction

Fig. 3 – Hybrid rocket firing test

Fig. 1 – Mold preparation, casting, before firing,

after firing (from left to right).

Fig. 4 – Regression rate as a function of

oxidizer mass flux.

Fig. 5 – Specific impulse as a function of

equivalence ratio.

Regression rate is the speed at which the fuel isconsumed. Fig. 4 shows that the hot engines havea higher regression rate than their correspondingcold engine. (The pairs are represented with thesame marker shape).

Fig. 5 indicates that the hot and cold pairs have avery similar specific impulse, which is the changein momentum per unit of fuel. This means that theinitial temperature of the fuel doesn’t significantlyinfluence the rockets’ performance.

The purpose of our research was to analyze the influenceof the fuel’s initial temperature on the performance ofhybrid rockets combusting paraffin wax with gaseousoxygen. About 20 paraffin engines were casted and testedat initial temperatures of -20°C and +30°C.

Abstract