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Development and evaluation of thermal protection material for solid rocket motors
Thesis (MEng)--Stellenbosch University, 2022.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2022
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| _version_ | 1867613913339658240 |
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| access_status_str | Open Access |
| author | Rheeder, Amy |
| author2 | Knoetze, Johannes Hendrik |
| author_browse | Knoetze, Johannes Hendrik Rheeder, Amy |
| author_facet | Knoetze, Johannes Hendrik Rheeder, Amy |
| author_sort | Rheeder, Amy |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2022. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/124739 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:43:41.995Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/124739 Development and evaluation of thermal protection material for solid rocket motors Rheeder, Amy Knoetze, Johannes Hendrik Stellenbosch University. Faculty of Engineering. Dept. of Process Engineering. Insulation (Heat) Thermal protection Solid propellants Solid rocket motor UCTD Thesis (MEng)--Stellenbosch University, 2022. ENGLISH SUMMARY: Solid Rocket Motors (SRMs) produce thrust by converting a solid propellant into a high volume of extremely hot gas (up to 3500 K). Propellant is often housed in a lightweight composite casing with low heat resistance and strict operational temperature limits. In order to shield the casings from the combustion environment, an insulation layer is incorporated in the design. The insulation layer typically consists of a filled elastomer material. These materials have demanding requirements in terms of thermal and mechanical properties. A simplified ablation heat transfer model was developed as part of the study as a tool for material evaluation. This model was found to have good agreement with an established ablation model in predicting SRM casing temperatures. The measured material properties were used as an input to the ablation model to assess material performance. The purpose of this study was to investigate the effects of varying composition of EPDM materials on the performance of an insulation. The fibre type (Kynol or Twaron) and content, silica powder content, curing agent (peroxide or sulfur), EPDM grade, and curing conditions were varied to study the effects on material properties. The materials were evaluated according to their thermal (heat capacity, thermal conductivity and char yield) and mechanical properties (tensile strength, elongation at break, density and hardness). An ablation test was also conducted to assess materials’ ablation resistance. The study found that curing agents and curing conditions had negligible effect on the material properties. The EPDM selection had an effect on tensile strength as well as processing behaviour of the materials. The filler content, i.e. Twaron, Kynol, and silica, were found to have the most significant effect on material properties. Increased fibre content correlated well with improved ablation resistance. The addition of fibres increased ablation resistance of materials by 52-335% compared to material samples containing only silica. Fibre selection played a role in the ablative performance of the materials, with Twaron materials outperforming Kynol materials by 59-65%. The presence of fibres in a material negatively impacted the processing characteristics and the tensile strength and elongation of the materials. The silica content had a significant effect on the tensile strength, density and char yield of the materials. The fibre selection also had a significant impact on the thermal conductivity (0.181-0.238 W/mK) and heat capacity of the materials (1550-2360 J/kgK). Kynol produced materials with 24-31% lower thermal conductivity, and 20-35% lower heat capacity compared to materials containing Twaron. After evaluating the materials according to the measured properties and predicted performance in the ablation model, the best performing composition was identified as a material containing 10 phr silica powder and 10 phr Twaron pulp. AFRIKKANS OPSOMMING: Vastedryfmiddel vuurpylmotors produseer stukrag deur die omskakeling van vastedryfmiddel na ’n groot volume uiters warm gas (temperatuur tipies 3200-3500 K). ’n Liggewig saamgestelde huls word tipies gebruik om die dryfmiddel te huisves. Sulke hulse het ’n lae weerstand teen hoë temperature en is onderworpe aan streng temperatuur beperkings. Om die hulse teen die ontbrandingsomgewing in die motor te beskerm word ’n isolasie laag in die ontwerp ingesluit. Die isolasie laag is tipies ’n gevulde elastomeer. Hierdie materiale moet aan streng vereistes ten opsigte van meganiese en termiese eienskappe voldoen. Die doel van hierdie studie was om die effek van wisselende komposisies van EPDM (Etileen Propileen Diene Monomeer) materiale op die eienskappe van die isolasie te ondersoek. Die eksperimentele ontwerp, wat volgens die Taguchi metode gedoen is, het gelei tot ’n doeltreffende ontwerp. Die tipe vesel (Kynol of Twaron) en inhoud, silika poeier inhoud, kuurmiddel (peroksied of swael), EPDM graad, en kuurtoestande is gevarieer om die impak op materiaaleienskappe te bestudeer. Die materiale is ge-evalueer volgens die termiese (hitte kapasiteit, termiese geleiding en verkoling) en meganiese eienskappe (treksterkte, verlenging by breek, digtheid en hardheid). Die materiale se weerstand teen ablasie is ook geassesseer in ’n ablasie toets. ’n Vereenvoudigde ablasie hitte-oordrag model is ontwikkel wat vir materiaal evaluasie gebruik kan word. Die model se vuurpylhuls temperatuur voorspellings het goeie ooreenkoms met ’n gevestigde ablasie model se resultate getoon. Die gemete materiaal eienskappe is gebruik as insette vir die ablasie model om elke materiaal se werkverrigting te evalueer. Die ondersoek het gevind dat kuurmiddels en kuur toestande ’n weglaatbare effek op die materiaal eienskappe gehad het. Die keuse van EPDM graad het ’n impak gehad op die treksterkte en die prosesseringseienskappe van die materiale. Die vuller inhoud, m.a.w. Twaron, Kynol en silika, blyk die grootste effek te hê op die materiaal eienskappe. Hoër vesel inhoud het gelei tot verhoogde ablasie weerstand. Die gebruik van vesels het die ablasie weerstand van materiale met 52-335% verhoog in vergelyking met materiaal monsters wat slegs silika bevat. Twaron materiale het 59-65% hoër ablasie weerstand getoon as Kynol materiale. Die teenwoordigheid van vesels het ’n negatiewe impak op die prosesseringseienskappe, asook op treksterkte en verlenging by breek gehad. Silika inhoud het ’n beduidende invloed op die treksterkte, digtheid, en verkolingsopbrengs van die materiale gehad. Die tipe vesel wat gebruik is het ’n beduidende impak gehad op die termiese geleiding en hitte kapasiteit van die materiale. Materiale wat Kynol bevat het, het 24-32% laer termiese geleiding en 20-35% laer hitte kapasiteit vertoon in vergelyking met materiale wat Twaron bevat het. Evaluering van die materiale volgens die gemete eienskappe en voorspelde werkverrigting in die ablasie model toon dat die materiaal met die beste eienskappe ’n vesel inhoud van 10 phr Twaron, en 10 phr silika poeier bevat. Masters 2022-03-09T09:27:47Z 2022-04-29T09:29:40Z 2022-03-09T09:27:47Z 2022-04-29T09:29:40Z 2022-04 Thesis http://hdl.handle.net/10019.1/124739 en_ZA Stellenbosch University xix, 174 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Insulation (Heat) Thermal protection Solid propellants Solid rocket motor UCTD Rheeder, Amy Development and evaluation of thermal protection material for solid rocket motors |
| title | Development and evaluation of thermal protection material for solid rocket motors |
| title_full | Development and evaluation of thermal protection material for solid rocket motors |
| title_fullStr | Development and evaluation of thermal protection material for solid rocket motors |
| title_full_unstemmed | Development and evaluation of thermal protection material for solid rocket motors |
| title_short | Development and evaluation of thermal protection material for solid rocket motors |
| title_sort | development and evaluation of thermal protection material for solid rocket motors |
| topic | Insulation (Heat) Thermal protection Solid propellants Solid rocket motor UCTD |
| url | http://hdl.handle.net/10019.1/124739 |
| work_keys_str_mv | AT rheederamy developmentandevaluationofthermalprotectionmaterialforsolidrocketmotors |