Cooling concept for combustion pistons: Development, Design and Simulation
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
The cooling of combustion pistons is an important process during energy conversion. In car engines this is done by oil, which at the same time is offering lubrication. This work is focusing on an alternative energy converter, a free-piston linear generator of the German Aerospace Center, which is using solid lubricated pistons to avoid oil deposition within the combustion chamber. In doing so, emissions can be reduced but a new way of cooling the piston is needed to continuously guarantee functioning at optimal performance. Concepts were generated systematically and evaluated on their degree of fulfilment. The selected concept guarantees heat extraction at the piston by using the oscillating motion of the components to impose a directed coolant flow between the piston and the colder gas spring. To identify the efficiency, the analysis was divided into two steps: Heat transport analysis at predefined mass-flow rates and coolant transport analysis at different oscillation frequencies. The results, which were achieved by an analytical, numerical and experimental approach, showed great potential of the heat transport processes; as the pistons temperature was not exceeding the defined limits. Also the coolant transport processes were confirmed at low frequencies.
Place, publisher, year, edition, pages
2016. , 70 p.
Heat extraction, alternative energy converter, innovative piston cooling, thermal resistance network, computational fluid dynamics and heat transfer analysis, analytical and numerical analysis
Engineering and Technology
IdentifiersURN: urn:nbn:se:hj:diva-31712ISRN: JU-JTH-PRU-2-20160054OAI: oai:DiVA.org:hj-31712DiVA: diva2:967823
German Aerospace Center
Subject / course
JTH, Product Development