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Technical Paper

LHP Modeling With EcosimPro and Experimental Validation

Loop Heat Pipes (LHPs) are two phase heat transport devices where the fluid circulation is achieved by capillary forces. Because of their high heat transport capability, robustness, reliability and compactness, they are becoming standard thermal control devices in several applications in space, aeronautics and electronics industry. Several mathematical models have been developed to predict the behavior of these devices. However, due to the complexity of the two-phase phenomena involved in LHPs, current models cannot simulate several performance characteristics. This paper presents an LHP mathematical model developed using the software simulation tool EcosimPro. The results of the mathematical model have been compared with the hardware test data for code validation. Results in both, steady and transient conditions, are presented and discussed.
Technical Paper

Advances in Two-Phase Loop with Capillary Pump Technology and Space Applications

Two-Phase Loops with Capillary Pump (Loop Heat Pipes (LHP) and Capillary Pumped Loops (CPL)) are currently among advanced thermal control technologies for aerospace applications. Large numbers of experimental and operational two-phase loops were successfully tested and used in several spacecraft in the past two decades. Novel technologies such as Advanced CPL-LHP, High Performance CPL, miniature LHPs, inversion (reversible, “Push-Pull") LHPs, ramified, multiple evaporator and condenser LHPs and CPLs, for complex thermal control systems are being proposed. This paper presents a state-of-the-art survey and analysis of these technologies. A classification of Two-Phase Loop with Capillary Pump designs is recommended. Basic principles, operational conditions and characteristics, temperature control and start-up initiation are discussed. The use of thermal control systems based on Two-Phase Loops with Capillary Pump for space applications is reviewed and summarized.
Journal Article

A New Method for Monitoring Gears Surface Failures Using Enhanced Image Registration Approach

In this paper, we present an image registration approach to cope with inter-image illumination changes of arbitrary shape in order to monitor the development of micro-pitting in transmission gears. Traditional image registration approaches do not typically account for inter-image illumination variations that negatively affect the geometric registration precision. Given a set of captured images of gear surface degradation with different exposure times and geometric deformations, the correlation between the resulting aligned images is compared to a reference one. The presented image registration approach is used with an online health monitoring system involving the analysis of vibration, acoustic emission and oil debris to follow the development of micro-pitting in transmission gears. The proposed monitoring system achieves more registration precision compared to competing systems.