Inst. d'Electron. et de Microelectron. du Nord, UMR-CNRS 9929, Dept. ISEN, 41 boulevard Vauban, 59046 Lille Cedex, France
Eramer, 83500 La Seyne sur Mer, France
DCN-Ingenierie Sud, 83140 Six Fours les Plages, France
Heating has become a critical issue for low-frequency projectors due to their high dissipated power density and long excitation time. In this paper, the cooling of sonar projectors in terms of heat transfer optimization is presented. An analysis of the projector heating requires the description of the heat conduction in the structure and the heat exchanges with the surrounding medium. This analysis is performed in steady state using both analytical (thermoelectrical analogies) and numerical (finite element) models. For the reference transducer (double-ended longitudinal piezoelectric vibrator), the temperature distribution and heat fluxes are computed. The temperature decrease and the importance of various heat paths are evaluated for various techniques of cooling. Practical considerations (simplicity, fiability, cost, size) and cooling efficiency are both taken into account to determine the optimal solution. At constant dissipated power density, the maximum temperature is theoretically divided by 3. Temperature measurements on reference and optimized projectors are provided and compared to predictions. Extension of the technique to other geometries of projectors and other types of active materials (magnetostrictive, electrostrictive) is discussed.