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Flight Controls and Environmental Control Systems
Published in Stephen J Wright, Aviation Safety and Security, 2021
A typical commercial aircraft has a maximum take-off mass greater than 5,700 kg and a cruising altitude that can range from 25,000 to 41,000 ft (Airbus 1992). At these altitudes, the outside temperature can fall to below −57°C and have a local outside air pressure of around 3 pounds per square inch (0.3 bar). To keep the passengers in relative comfort (and alive), it is critical to pressurise the aircraft to allow for effective human respiration, and to warm the passenger cabin. The air-conditioning system, which is also known as the Environmental Control System (ECS), is a vital system fitted to all large aircraft. Without an operational ECS at altitude, the occupants of an aircraft would suffer the effects of hypoxia and the extreme cold. Exposure to atmospheric conditions at high altitudes (c. 40,000 ft) in the absence of a functioning ECS will usually result in incapacitation after 30 seconds, leading to permanent incapacitation (death) thereafter (Airbus 1992).
Experimental and CFD analysis of multi nozzle ejector system for aircraft compact heat exchanger applications
Published in Australian Journal of Mechanical Engineering, 2023
L. Sheik Ismail, N. Govindha Rasu, V. Krishnaprasad, Ch Ranganayakulu
Compact heat exchangers (CHEs) finds many applications in many fields (viz., automobiles, Marine, aircraft, refrigeration and cryogenic systems). In fighter aircraft, the CHEs are used in the environmental control system (ECS). In this application, the hot gases from the engine are passed through the series of compact heat exchangers to cool it to the required low temperature (~5°C) needed by ECS. During flight, cooling air (secondary fluid) for the heat exchanger is obtained by ram air taken through intake of the duct leading to heat exchanger. However, ECS has to function, even when the aircraft is on ground. For this purpose, an air ejector system is used downstream of the compact heat exchanger, to suck ambient air through the intake duct. Thus, the performance of the CHEs depends directly on the performance of the ejector system, once the aircraft is on ground.
Analysis of the performance optimisation parameters of shell and tube heat exchanger using CFD
Published in Australian Journal of Mechanical Engineering, 2023
Ahmad Hanan, Umer Zahid, Tariq Feroze, Sohaib Z. Khan
Using a non-dominated sorting genetic algorithm (NSGA II) and ANSYS FLUENT 14 software, heat exchange in the air to water heat exchanger employing the use of either typical or perforated helical fins was examined. Further investigation was done by varying pitch ratio, open area ratio, and Reynolds number (Sheikholeslami and Ganji 2016). For an effective simultaneous component and system design, flow geometry enhancement in a counter-current flow heat exchanger was done for a vapour-compression refrigeration cycle of aircraft environmental control system. System optimisation was accomplished in terms of reduced power consumption and entropy generation minimisation (Shiba and Bejan 2001). Similarly, in another case, the salient geometric features of a counter-flow heat exchanger in an aircraft environmental control system were determined. By considering the effects of the finned surface and smooth-plate surface, overall system optimisation was investigated and thereby realised (Jose 2001).
Bayesian Network–Based Fault Diagnostic System for Nuclear Power Plant Assets
Published in Nuclear Technology, 2023
Xingang Zhao, Xinyan Wang, Michael W. Golay
A large body of work provides details about using the BN approach for diagnostics in several industries outside the nuclear field. Liu et al.4 presented a BN-based fault diagnosis method for a commercial aircraft environmental control system and used a multi-information fusion mechanism to incorporate first principles, expert experience, and condition monitoring data into the system. Adedipe et al.5 reviewed the state-of-the-art and future developments on the adoption of BN models in the wind energy industry. Jun and Kim6 developed a fault analysis method using BN for a centrifugal compressor with a focus on fault identification, inference, and sensitivity analysis. Huang et al.7 proposed a multiple-symptoms-oriented BN diagnostic model for a vehicle infotainment system. Khanafer et al.8 introduced a BN-enabled automated diagnosis model to troubleshoot in a third-generation mobile cellular system. Other examples of areas where BNs have seen applications are industrial processes,9 hydroelectric generation systems,10 and ground-source heat pumps.11