EXPERIMENTAL INVESTIGATION ON A LAB-SCALE HYBRID ROCKET BURNING N2O/ PARAFFIN-BASED FUEL AND N_2O/METAL-LOADED HTPB

摘要

In the effort of increasing the notoriously slow fuel-regression rate of hybrid rockets, two approaches, both focused on the fuel nature, are investigated in this paper: addition of metal particles to HTPB grains against the use of paraffin-based fuels, which are expected to raise more significantly the regression rate. A series of firing tests on two lab-scales hybrid rocket engines have been carried out with gaseous nitrous oxide and pure HTPB, aluminium-loaded HTPB or paraffin wax. Scale effects are examined. Outcomes are discussed in terms of fuel regression rate and combustion efficiency. A comparison with the data retrieved from pure HTPB or metal-loaded HTPB burnt with gaseous oxygen is also drawn. Both aluminium-powder addition to HTPB and the use of paraffin-based fuel appear to increase regression rate, the latter showing the major gain. In particular aluminium powder addition seems to increase regression rate more than observed with oxygen.