Comparative Full Fire Test Evaluation of Hybrid Fuel Experimental Engine with CFD Analysis
2nd International Kosovo Academic Research Congress, Priştine, Kosova, 26 Şubat - 28 Mart 2026, cilt.1, sa.1, ss.794-808, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Cilt numarası: 1
- Doi Numarası: 10.30546/19023.978-9952-610-31-4.2025.5097
- Basıldığı Şehir: Priştine
- Basıldığı Ülke: Kosova
- Sayfa Sayıları: ss.794-808
- Süleyman Demirel Üniversitesi Adresli: Evet
Özet
Hybrid rocket propulsion systems offer operational safety and throttling capability by combining a solid fuel grain with a liquid oxidizer. However, performance largely depends on injector atomization quality, turbulence-chemistry interaction, and heat feedback to the fuel surface. This study aims to systematically evaluate injector type selection and combustion model selection for a 1 kN class LOX-paraffin hybrid rocket engine. The SH4 shower head injector configuration was chosen as the base geometry due to its high hole density and improved oxidizer dispersion properties. The selected injector geometry consists of 71 axial holes with a diameter of 0.8 mm. This configuration increases oxidizer mass flux uniformity and promotes improved near-wall mixing. The target chamber pressure for the hybrid engine is 25 bar with an oxidizer mass flow rate of approximately 550 g/s and an O/F ratio of 7.8. The nozzle throat diameter is 22 mm. These parameters define the reference combustion environment for CFD prediction and experimental verification. This study presents an integrated computational and experimental investigation of the LOX-paraffin hybrid rocket engine with emphasis on injector geometry selection, combustion model comparison, and interpretation of fire test results through CFD analysis. The goal is to determine the optimal injector configuration and turbulence-combustion modeling strategy that accurately predicts chamber performance while providing a validated framework for experimental fire testing. Comparative analyzes between turbulence models (Realizable k–epsilon, k–omega SST and LES) and combustion models (EDM, EDC and PDF transfer) are presented. CFD predictions are interpreted based on fire test performance measurements including chamber pressure, regression rate, thrust, and specific thrust. Three combustion modeling strategies were evaluated: Eddy Distribution Model (EDM), Eddy Distribution Concept (EDC), and Probability Density Function (PDF) transport modeling. The EDM approach assumes mixing-limited reaction rates and often underestimates the peak flame temperature. The EDC model provides improved wall heat flux prediction by incorporating finiterate chemistry within turbulent microstructures. The PDF transport model statistically resolves the turbulence-chemistry interaction and captures localized flame structures with higher accuracy