Pioneer exploration on the energy recovery technology for waste heat in solid rocket motors by utilizing thermoelectric materials

Solid rocket motors (SRMs) have demonstrated extraordinary performance. Heat waste in the tail flame, however, means that improving the efficiency of rocket energy utilization remains a challenge. In this research, we proposed the concept of recovering the enormous combustion energy of rockets. We built a small SRM, placed different thermoelectric modules (TEMs) in the tail flames, and studied the influence of cooling water-flow rate, jet distance, number of PN junctions, and combination of TEMs on output energy and efficiency. The results demonstrated that the jet distance could improve the output energy and energy conversion efficiency of the TEMs, but if the jet distance was too short, it would lead to the failure of the TEMs. In addition, we found that with an increase in the cooling water-flow rate, the output electric energy first increased and then decreased, and the energy conversion efficiency first decreased and then increased. Finally, we found that with an increase in the number of PN junctions, the output energy increased but the energy conversion efficiency remained nearly unchanged. The proposed energy recovery device had an output power of up to 1221 W/m², which represented performance superior to that of previous thermoelectric power generation technologies. These findings provide insight into the optimization of thermoelectric power generation technologies and further progress the efficiency of SRMs.