A non-conventional five piston double.-acting Stirling Engine filling system CFD simulation and experimental validation

01/09/2016 1 A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation Marta CORDON, Aida AUÑÓN, Igor BARRENO, Mauricio ESKUBI, Juan Antonio AUÑÓN. Contents 1. Introduction 2. Analysis base model 3. Theoretical Analysis 4. Experimental Analysis and Discussion 5. Conclusions 6. Future proposals 7. Acknowledgements 8. References A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 2 01/09/2016 2 1. Introduction •What is new in this engine? •Goal: Analysis of the working cycle of the new design •Means: Real engine working in laboratory and theoretical model for its analysis (COMSOL Multiphysics). A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 3 2. Analysis Base Model •Common volume joining all filling channels. •Small holes connecting filling to pistons. •Pressure analysed. A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 4 NOT SCALED 01/09/2016 3 2. Analysis Base Model A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 5 2.1. Theoretical analysis applied •Navier-Stokes equation including heat transfer                 2 3           0              A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 6 01/09/2016 4 2.1. Theoretical analysis applied •When viscous heating and pressure work is considered:                      |            2 3  :  A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 7 3. Theoretical analysis A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 8 A first model in 3D of a single piston was first done 01/09/2016 5 3. Theoretical analysis A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 9 The second model was again of one piston and in 2D, to ease the computational cost. 3. Theoretical analysis A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 10 The third model was with two pistons to analyse the influence of the connection between them. 01/09/2016 6 3. Theoretical analysis A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 11 Fourth and last model has 5 pistons to fully analyse the connection and its effect in the pressure. 3.1. Calculation and results A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 12 •Results obtained in the different models analysed confirmed the theory. •Representation of the variation of the pressure in the connecting channel in one of the models. 01/09/2016 7 3.1. Calculation and results Pi Photmax Pcoldmax Pconnec 0.2 0.58 0.55 0.58 0.55 1.12 0.81 0.93 1.07 1.56 0.90 1.13 1.3 2.02 1.11 1.45 560000 565000 570000 575000 580000 585000 590000 005 005 006 006 006 006 006 Pressure (pascal) Time (s) Pressure P1hot P1cold Pcon A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 13 •Final results in the 5 pistons model with different initial pressures. Megapascals 3.1. Calculation and results A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 14 •Representation of the pressure in one specific time for the 5 pistons. 01/09/2016 8 3.1. Calculation and results A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 15 •Representation of the pressure in one specific time for the 1 piston. 4. Experimental analysis and discussion •Pressure values obtained in the real engine while functioning. A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 16 01/09/2016 9 5. Conclusions •A non-conventional five piston double-acting Stirling engine filling system is presented. Innovation introduced: no moving mechanical parts which allows identical pressure in all pistons easily. •A one-cylinder model has been considered studying the influence of the hole geometry in the resulting pressure drop. The model has been modified to adjust to real engine until five cylinders where considered. A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 17 5. Conclusions •Main conclusion: each working volume work independently from the others and from the common volume of the filling system, which remains at constant pressure. Thus, this common volume does not actuate as a dead volume with its dramatic influence in the engine performance. A non-conventional five piston double-acting Stirling Engine filling system CFD simulation and experimental validation 18 due to a viscous fluid moving. The equations related to this two “sub physics” are: