This paper describes computational fluid dynamics applied to the analysis of a hybrid rocket motor with a diaphragm in the combustion chamber to enhance rocket performance. This work follows the last author’s experiments: An engine was tested with nitrous oxide and paraffin wax as propellants. Several of the tests have been used as references for numerical simulations. The following approximations have been made: steady-state conditions, eddy dissipation model with one-step reaction, gaseous injection of fuel and oxidizer, and no droplets entrainment (typical of a paraffin grain). First of all, a single geometry without a diaphragm has been analyzed with different turbulence models ( k - ω , k - ω shear stress transport, k - ε , k - ε renormalization group). It has been shown that the k - ω model predicts a lower flame temperature and chamber pressure than the k - ε model. Then, five geometries have been studied to compare two different types of diaphragms (one hole and four holes) in two positions (24 and 33% of the total length) to a configuration without any mixer. The effect of the diaphragm is to increase the mixing of the chemical species participating in the combustion process. The use of the diaphragm causes a performance enhancement, as shown in the experimental study. There is a good agreement between computational fluid dynamics results and experimental data: The efficiency is overestimated by less than 5.5%. This work proves the capability of computational fluid dynamics to predict global hybrid rocket performance: It can be considered as a useful tool in the study of mixing devices.


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    Title :

    Investigation of Effect of Diaphragms on the Efficiency of Hybrid Rockets


    Contributors:

    Published in:

    Publication date :

    2013-12-31


    Size :

    11 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English





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