摘要: In this paper ultrasound diagnostics are exploited for the material structural integrity evaluation of paraffin-based fuels used for hybrid rocket engines. Mainly, ultrasound is used to measure the regression rate of these fuels. ... 展开 In this paper ultrasound diagnostics are exploited for the material structural integrity evaluation of paraffin-based fuels used for hybrid rocket engines. Mainly, ultrasound is used to measure the regression rate of these fuels. The evaluation has been carried out for solid fuel disks of a hybrid rocket engine with non-conventional configuration, the SPLab vortex flow pancake (SVFP). For the SVFP grains the regression rate was determined by pre- and post-firing analysis of the grains. Investigated fuel formulations are based on a commercial microcrystalline wax (W1) blended with a reinforcing polymer (SEBS-MA). Reinforcing polymer mass fraction in the blends spanned from 5% (W1S05) to 20% (W1S20). The propagation velocity of US waves inside the test samples was estimated to be in the range 2131 m/s (W1S05) to 2017 m/s (W1S20). Finally, the estimation of the regression rate of VFP disks was compared with the standard data reduction procedure based on thickness over time method. Results showed errors ＜ 10% for all the tested fuels. Such a difference in the regression rate does not influence the dependence of this parameter on the oxidizer mass flux. In general, ultrasounds show an underestimation of the regression rate, with respect to the thickness over time technique. Regression laws displayed similar curve trends, yet underestimate the predicted regression rate values. 收起