Active Thermal Management Strategy and Mathematical Modeling for System-Level Packaged Modules in Logging-While-Drilling Systems

As exploration activities progress into deeper geological formations, the drilling systems utilized for exploration encounter more demanding high-temperature environments. This study presents the design of an active thermal management system that integrates thermoelectric cooling technology for a downhole drilling system operating at an ultra-high temperature of 225°C. A structural model was established for the system, and the thermal resistances of each module were decomposed according to the thermal flow path into equivalent thermal resistances of various shapes, including trapezoidal and sector shapes, thereby constructing a thermal resistance network. Based on this thermal resistance network, a computational expression for the chip temperature was derived. After establishing a comprehensive theoretical model, simulations were conducted for validation, confirming the validity of the expression, with simulation results differing from calculated values by approximately 0.5%. This provides a basis for the subsequent optimization of the overall structure.