Numerical simulation for the performance analysis of a gamma Stirling engine prototype
(English)Manuscript (preprint) (Other academic)
Computer assisted modelling and simulation of energy systems asses the performance and suggest improvements to achieve energy efficient solutions. This is the case of the Stirling engine technology, where computer simulations combined with experimental work have helped to the development of different prototypes. Following this trend, the current work aims to study possible improvements towards the design of a gamma Stirling engine prototype through numerical simulations. The prototype was first experimentally studied and presented low performances. For this reason and considering a lack of reports for this prototype, the numerical simulation was the approach to identify the possible problems that limited the performance. In this regard, this paper presents the development and validation of a numerical model that represent the performance of the Stirling prototype. The model follows a modular approach considering ideal adiabatic working spaces; limited internal and external heat transfer through the heat exchangers; and mechanical and thermal losses during the cycle. In addition, it includes the calculation of the mechanical efficiency taking into account the crank mechanism effectiveness and the forced work during the cycle. Consequently, the model aims to predict the work that can be effectively taken from the shaft. The model was compared with experimental data obtained in an experimental rig built for the engine prototype. The results showed an acceptable degree of accuracy when comparing with the experimental data, with errors ranging from 1%-8% for the temperature in the heater side, less than 1% error for the cooler temperatures, and 1-8% for the brake power calculations. Therefore, the model was probed adequate for study the prototype performance. In addition, the results of the simulation reflected the limited performance obtained during the prototype experiments, and a first analysis of the results attributed this to the forced work during the cycle. The implemented model is the basis for a subsequent parametric analysis that will complement the results presented.
Stirling engine; simulation
Research subject Energy Technology
IdentifiersURN: urn:nbn:se:kth:diva-163051OAI: oai:DiVA.org:kth-163051DiVA: diva2:798497
FunderSida - Swedish International Development Cooperation Agency
QS 20152015-03-262015-03-262015-03-27Bibliographically approved