Eventos Anais de eventos
ENCIT 2020
18th Brazilian Congress of Thermal Sciences and Engineering
NUMERICAL STUDY OF MASS TRANSFER BETWEEN TWO ALPHA STIRLING CYCLES
Submission Author:
MARIANA VALASKI , PR , Brazil
Co-Authors:
MARIANA VALASKI, Luís Mauro Moura, Paulo Philippi, Stephan Hennings Och
Presenter: MARIANA VALASKI
doi://10.26678/ABCM.ENCIT2020.CIT20-0393
Abstract
The main characteristic of the Stirling cycle is external combustion, which does not depend on a specific heat source for the production of mechanical work. As a result, it has aroused interest in scientific studies on the transformation of thermal energy by renewable sources. The objective of the work is to present a numerical analysis of two outdated alpha Stirling cycles that exchange mass with each other in order to modulate the work performed. For this study, an algorithm for the thermodynamic system was written using the model proposed by Urieli that presents the cycle as being adiabatic, without loss of mass for the external environment, perfect regeneration and ideal gas. The first stage of this model is the simulation of the simple cycle and in a second moment it is necessary to solve the equations of the model of Urieli modified in the conditions of mass and energy balance, interconnecting the cycles by means of mass transfer considered instantaneous. at a given valve opening, adiabatic, isothermal and without friction losses. The results of the numerical analysis as being a simple cycle, were generated and compared with data from the literature, the cycle without mass transfer presented thermal efficiency of 60% and with mass transfer of 67%, this efficiency increase is due to the gain of energy from the hot source, which exceeds the value of work lost by the drop in pressure. There is a limit of mass transfer, so that the laws of physics are respected and the efficiency does not exceed numerically that of Carnot. In addition, it is necessary to pay attention to the fact that the valves must only be opened when there is a pressure difference between the cycles, allowing the passage of the mass from the higher pressure compartment to the lower one.
Keywords
Stirling Alfa, mass transference, Urieli.
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