Researcher:
Kahraman, Büşra

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Master Student

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Büşra

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Kahraman

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Kahraman, Büşra

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20201

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    Hybrid rocket nozzle erosion with microaluminum-added fuel
    (Amer Inst Aeronautics Astronautics) Karakas, Hakki; Ozkol, Ibrahim; N/A; Department of Mechanical Engineering; Department of Mechanical Engineering; Kahraman, Büşra; Karabeyoğlu, Mustafa Arif; Master Student; Faculty Member; Graduate School of Sciences and Engineering; College of Engineering; N/A; 114595
    Because of its relatively low cost and wide availability, carbon graphite is one of the most widely used ablative nozzle materials in hybrid rocket propulsion. The erosion characteristics of the nozzle material have paramount importance because it directly influences the I-sp performance. This is especially the case for upper-stage or in-space rocket motors operating with very long burn times. In this study, the effect of aluminum-added fuel on the graphite nozzle erosion is studied. In the experimental studies, a high regression rate paraffin-based fuel is loaded with micrometer-size aluminum powder for nozzle erosion reduction. In our approach, aluminum is added at high concentrations as a fuel ring in front of the main paraffin-based fuel which contains no aluminum. Based on the motor tests conducted with gaseous oxygen as an oxidizer, it is shown that aluminum addition decreased the nozzle erosion rate up to 45% and increased the nozzle erosion onset time by 1 to 3s. The new method of introducing an energetic powder in a fuel ring positioned at the fore end of the motor offers an easy and scalable way of reducing the nozzle erosion and improving the I-sp performance of the rocket motor.
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    Erosion rate investigation of various nozzle materials in hybrid rocket motors
    (American Institute of Aeronautics and Astronautics, 2020) Karakaş, Hakkı; Nimet Eren, B.; Department of Mechanical Engineering; N/A; Department of Mechanical Engineering; Kahraman, Büşra; Karabeyoğlu, Mustafa Arif; Faculty Member; Master Student; College of Engineering; Graduate School of Sciences and Engineering; 114595; N/A
    Thrust profile is very important for rocket motors. Nozzle design is a key parameter to predict thrust profile. Increase in nozzle throat area is very important for the system performance because Isp changes when the throat area changes. Pressure decreases when throat area increases and this might cause a stability problem. Mechanical and chemical erosions can occur in nozzle throat. Due to high oxidizing agents in oxidizers of hybrid rocket motors and combustion products of fuel and oxidizer, chemical erosion can be seen in hybrid rocket motor nozzles. Consequently, operating at low O/F ratios can decrease erosion rate of nozzle throat due to low oxidizing agents. Additionally, higher chamber pressure means higher erosion rates due to increase in mass fluxes and heat transfer at nozzle throat. Fuel formulation also plays an important role in reducing nozzle erosion. Metal additives such as Al and Mg significantly reduce nozzle erosion since Al2O3 formation decreases the mass fraction of oxidizing agents. The most important thing that decreases nozzle erosion is the selection of nozzle material. Different graphite types and molybdenum tested as nozzle material for this study.