To address the thermal management requirements of high-heat-flux electronic equipment in aerospace applications, a radial-flow sector-shaped plate-fin evaporator operating under consumable cooling conditions was investigated. The key structural parameters of the evaporator were preliminarily selected through numerical simulations. An open-loop experimental platform was established, utilizing an antifreeze fluid loop to simulate onboard thermal loads, enabling experimental testing of the flow and heat transfer characteristics of the expendable evaporator under typical operating conditions. The experimental results indicate that the impact of flow direction on the performance of radial flow sector plate fin evaporators exhibits significant dependence on operational conditions, with distinct crossover features between parallel flow and counter flow observed in medium-low and high thermal load ranges. In low-medium thermal load ranges, parallel flow demonstrates superior heat exchange performance due to the maximum initial temperature difference at the inlet section of the flow channel. However, under high thermal loads, counter flow surpasses due to its ability to sustain continuous and stable heat transfer driving forces and liquid phase wetting conditions in the latter half of the flow channel. Combined with numerical simulations, the mechanisms of two flow directions-parallel and counter flow-on the flow and heat transfer characteristics were systematically studied. Through analysis of temperature fields, gas phase volume fractions, and velocity fields, it was found that the primary cause of performance differences lies in the different axial temperature matching relationships between hot and cold fluids established by the two flow modes. Counter flow, through its inherent reverse temperature profile characteristics, extends the length of liquid film wetting, optimizing the heat transfer process in high heat flux regions. This research provides experimental evidence and theoretical references for the design and operation methods of evaporators targeting high heat flux dissipation scenarios.

Aerodynamic heating and heat sink scarcity pose critical challenges for the Environmental Control System (ECS) and thermal management systems of supersonic civil aircrafts. Current research on ECS primarily focuses on subsonic aircraft, with insufficient attention to supersonic configurations, necessitating dedicated investigations into supersonic civil aircraft ECS. Considering the available heat sinks on the aircraft during supersonic flight, a ECS integrated into the fuel thermal management system with heat sink mode switching function is proposed. Thermodynamic modeling and simulation were conducted for the systems. Simulation analysis under typical flight mission profiles demonstrated that this integrated system satisfies critical thermal safety boundary conditions, including maintai-ning cabin supply air temperature below 18 °C and fuel temperature under 150 °C during supersonic cruise and dece-leration descent phases. The research reveals that when the design endurance increases during cruise phase or initial fuel temperature rises, relying solely on fuel heat sinks may result in system thermal endurance falling below design requirements. Switching to ram air heat sink mode in such scenarios can extend thermal endurance. During deceleration descent, simultaneous utilization of both fuel and ram air heat sinks becomes necessary, where thermal endurance becomes co-constrained by fuel temperature limits and supply air temperature requirements. Regulating the recirculating fuel flow rate and ram air flow rate can further extend thermal endurance under these dual constraints. The dual-heat sink mode switching strategy balances thermal safety and economy, providing theoretical support and enginee-ring optimization pathways for the design of integrated thermal management systems in supersonic civil aircraft.

The optical fiber pre-warning system (OFPS) has been gradually considered as one of the important means for pipeline safety monitoring. Intrusion signal types are correctly identified which could reduce the cost of troubleshooting and maintenance of the pipeline. Most of the previous feature extraction methods in OFPS are usually quested from the view of time domain. However, in some cases, there is no distinguishing feature in the time domain. In the paper, firstly, the intrusion signal features of the running, digging, and pick mattock are extracted in the frequency domain by multi-level wavelet decomposition, that is, the intrusion signals are decomposed into five bands. Secondly, the average energy ratio of different frequency bands is obtained, which is considered as the feature of each intrusion type. Finally, the feature samples are sent into the random vector functional-link (RVFL) network for training to complete the classification and identification of the signals. Experimental results show that the algorithm can correctly distinguish the different intrusion signals and achieve higher recognition rate.