• Journal of the Korea Institute of Military Science and Technology
• /
• v.19 no.1
• /
• pp.35-42
• /
• 2016

Modern aircraft is facing the increase of power demands and thermal challenges. In accordance with the application of more electric technology and advanced mission requirement, aircraft system requires increase of power generation and it cause increase of internal heat generation. Simultaneously, restrictions have significantly been imposed to the thermal management system. Modern aircraft must maintain low radar observability and infra-red signature. In addition, new composite aircraft skins have reduced the amount of heat that can be rejected to the environment. The combination of these characteristics has increased the challenges faced by thermal management. In order to mitigate the thermal challenges, the concept of system level thermal management should be applied and new modeling and simulation tools need to be developed. To develop and utilize system level thermal management technology, three key points are considered. Firstly, the performance changes of subsystems and components must be assessed at an integrated thermal system. It is because that each subsystem and component interacts with other subsystems or components and it can directly effects on overall system performance. Secondly, system level thermal management requirements and solutions must be evaluated early in conceptual design process as vehicle and propulsion system configuration decisions are being made. Finally, new component level thermal management technologies must focus on reducing heat generation and increasing the availability of heat sinks.

• Journal of Aerospace System Engineering
• /
• v.17 no.5
• /
• pp.11-18
• /
• 2023

The architecture of the Fuel Thermal Management System (FTMS) in a commercial aircraft engine was built to model and simulate the fuel system. The study shows the thermal interactions between the fuel and engine lubrication oil through the mission profile of a high bypass ratio, two-spool turbofan engine. Fuel temperature was monitored as it flowed through each sub-component of the fuel system during the mission. The heat load in the fuel system strongly depended on the fuel flow rate, and was significantly increased for the periods of cruise and descent with decrease of fuel flow rate, rather than for the periods of take-off. Due to the thermal interaction in the pump housing, the fuel temperature at the outlet of the low-pressure pump was increased (4.0, 9.2, and 30.0) % over the case without thermal interaction for take-off, cruise, and descent, respectively.

• Journal of the Korean Society of Safety
• /
• v.29 no.5
• /
• pp.60-66
• /
• 2014

Depending on the progress of the industrial advances, the use of the thermal oil system in the utility system has been increased, which became an important part in the operation of the plant. However, fire or explosion have occurred due to lack of risk awareness and safety management, more frequently than we know. In this study, by using a questionnaire, actual conditions of safety management in thermal oil system is surveyed and analyzed, it is composed of general, a safety status of the thermal oil system component and the stage of recognition and management in the thermal oil system. These results of this study can be used as basic data to the safety management and the accident prevention of fire or explosion in the workplace.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2839-2844
• /
• 2008

A PEMFC(proton exchange membrane fuel cell) is a good candidate for residential power generation to be cope with the shortage of fossil fuel and green house gas emission. The attractive benefit of the PEMFC is to produce electric power as well as hot water for home usage. Typically, thermal management of vehicular PEMFC is to reject the heat from the PEMFC to the ambient air. Different from that, the thermal management of PEMFC for RPG is to utilize the heat of PEMFC so that the PEMFC can be operated at its optimal efficiency. In this study, dynamic thermal management system is modeled to understand the response of the thermal management system during dynamic operation. The thermal management system of PEMFC for RPGFC is composed of two cooling circuits, one for controling the fuel cell temperature and the other for heating up the water for home usage. Dynamic responses and operating strategies of the PEMFC system are investigated during load changes.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.3
• /
• pp.986-993
• /
• 2012

The objective of this study is to investigate performance characteristics of the thermal management system for passenger hydrogen fuel cell vehicle under various operating conditions. The thermal management systems comprised of a stack cooling system, an electric device cooling system and an air conditioning system for a passenger room were tested with driving conditions. As a result, in highway driving mode, the cooling performance of the stack cooling system with air conditioning on condition was 28.8 % lower than that of the air conditioning off condition. And cooling load of the electric cooling system in the city driving mode was 65.6% higher than that of the highway driving mode.

• Transactions of the Korean hydrogen and new energy society
• /
• v.18 no.3
• /
• pp.292-300
• /
• 2007

A dynamic system model of a proton exchange membrane fuel cell(PEMFC) has been developed. The PEMFC of this study has large active area with water cooling in order to simulate the performance of the commercially viable PEMFC system for the transportation. A PEMFC stack model is a transient thermal model which is respond to the dynamic change of the coolant temperature and the flow rate. The dynamic cooling system model has been developed to determine the coolant flow rate and the coolant temperature. Prior to the system level study, thermal management criteria have been set up and brought to the control command of the cooling system. Since the system model is designed to evaluate the effect of thermal management on the system performance, it is attempted to determine the proper control algorithm of the cooling system so that the PEMFC system is working on the thermal management criteria. As a result of simulation, feedback controlled cooling system consumes less power and produce more power comparing with that of conventionally controlled cooling system.

• Transactions of the Korean hydrogen and new energy society
• /
• v.23 no.4
• /
• pp.323-329
• /
• 2012

A thermal management system of a proton exchange membrane fuel cell is taken charge of controlling the temperature of fuel cell stack by rejection of electrochemically reacted heat. Two major components of thermal management system are heat exchanger and pump which determines required amount of heat. Since the performance and durability of PEMFC system is sensitive to the operating temperature and temperature distribution inside the stack, it is necessary to control the thermal management system properly under guidance of operating strategy. The control study of the thermal management system is able to be boosted up with hardware in the loop simulation which directly connects the plant simulation with real hardware components. In this study, the plant simulation of fuel cell stack has been developed and the simulation model is connected with virtual data acquisition system. And HIL simulator has been developed to control the coolant supply system for the study of PEMFC thermal management system. The virtual data acquisition system and the HIL simulator are developed under LabVIEWTM Platform and the Simulation interface toolkit integrates the fuel cell plant simulator with the virtual DAQ display and HIL simulator.

• Transactions of the Korean hydrogen and new energy society
• /
• v.22 no.6
• /
• pp.852-858
• /
• 2011

This paper is aiming to estimate the mutual influence of the stack cooling performances with the operation modes of the thermal management system for the hydrogen fuel cell vehicles. The heat capacity of the thermal management system was measured by varying the operating modes such as stack cooling heat exchanger only (Mode 1), stack cooling and electric devices cooling heat exchangers (Mode 2), and stack cooling and electric devices cooling heat exchangers with an operation of the condenser (Mode 3).As the results, Performance of the thermal management system (TMS) at Mode 3 decreased up to 34.0%, compared with the result of the Mode 1. In addition, in order to optimize the performance of TMS, the entropy change of stack cooling heat exchanger using irreversibility analysis technique was analyzed with the relationship between entropy generation and entering air velocity of the thermal management system.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.2
• /
• pp.510-515
• /
• 2012

The objective of this study is to investigate low temperature performance characteristics of the thermosyphon with/without wick. Thermosyphons using water as the working fluid are tested with variations of wick, charge amount of the working fluid, outdoor temperature, and heat load for the evaporator section at a low temperature. As a result, the heat transfer of thermosyphon was optimized at the charge amount of 40% and increased with the rise of the outdoor temperatures.

• Proceedings of the SAREK Conference
• /
• 2005.11a
• /
• pp.329-334
• /
• 2005

As more high power wide band gap devices are being utilized. the thermal management issues associated with these devices need to be resolved. High power small devices dissipate excessive heat that must be cooled, but traditional cooling methods are insufficient to provide such a cooling means. This paper will evaluate a micro-capillary pumped loop thermal management system that is incorporated into the shim of the device, taking advantage of phase-change to increase the thermal conductivity of the system. The results of the modeling of the thermal management system will be discussed.