With the application of various high-power electronic devices to improving aircraft comprehensive performance, there has been a significant interest in the use of high heat flux dissipation technology to maintain an effective and safe operation for electronic devices. This article presents a numerical study on the thermal and electrical performance of the avionics server module by using single-phase immersion cooling technology with flow distributor and investigates the influence of heat dissipation capacity on the thermal performance of the avionics server module and DC IR-drop of printed circuit board power distribution network (PDN). The simulation results showed that a higher dielectric fluid flowrate can be provided b flow distributor with the same pumping power, and the maximum temperature of the hot spot was 4–8 °C lower than the module without a flow distributor. The result confirmed the improved flow performance and enhances heat transfer of the hot spot for the module with a flow distributor. However, the module without the flow distributor showed better comprehensive cooling performance with about 10–15% reduction in average Nusselt number with an increase in Re. The discrepancy of PDN DC IR-drop under different Re values was constant at 3% for different design geometries, which means the effect of the flow distributor on power delivery capability can be neglected.