An Axisymmetric Computational Fluid Dynamics Approach to the Analysis of the Working Process of a Solar Stirling Engine

2005 ◽  
Vol 128 (1) ◽  
pp. 45-53 ◽  
Author(s):  
K. Mahkamov

The use of computational fluid dynamics (CFD) models significantly extends the capabilities for the detailed analysis of the complex heat transfer and gas dynamic processes that occur in the internal gas circuit of a Stirling engine by more accurately predicting the engine’s performance. This accurate data on operational characteristics of the engine can then contribute to more precise calculations of the dimensions of a parabolic concentrator in a dish/Stirling engine installation. In this paper a successful axisymmetric CFD simulation of a solar “V”-type Stirling engine is described for the first time. The standard κ-ε turbulence model, with a moving mesh to reflect the reciprocating motion of the pistons, has been employed for the analysis of the engine’s working process. The gas temperature and pressure distributions and velocity fields in the internal gas circuit of the machine have been obtained and the pressure-volume diagrams have been calculated. Comparison of the numerical results produced from the axisymmetric CFD simulation of the engine’s working process with those computed with the use of second-order mathematical analysis shows that there are considerable differences. In particular, analysis of the data obtained indicates that the gas temperature in the compression space depends on the location in the cylinder for the given moment in the cycle and it may differ substantially from being harmonic in time.

Author(s):  
S N A Ahmad Termizi ◽  
C Y Khor ◽  
M A M Nawi ◽  
Nurlela Ahmad ◽  
Muhammad Ikman Ishak ◽  
...  

2013 ◽  
Vol 368-370 ◽  
pp. 619-623
Author(s):  
Zhen Liu ◽  
Xiao Ling Wang ◽  
Ai Li Zhang

For the purpose of avoiding the deficiency of the traditional construction ventilation, the ventilation of the underground main powerhouse is simulated by the computational fluid dynamics (CFD) to optimize ventilation parameters. A 3D unsteady RNG k-ε model is performed for construction ventilation in the underground main powerhouse. The air-flow field and CO diffusion in the main powerhouse are simulated and analyzed. The two construction ventilation schemes are modelled for the main powerhouse. The optimized ventilation scheme is obtained by comparing the air volume and pressure distributions of the different ventilation schemes.


2013 ◽  
Vol 368-370 ◽  
pp. 599-602 ◽  
Author(s):  
Ian Hung ◽  
Hsien Te Lin ◽  
Yu Chung Wang

This study focuses on the performance of air conditioning design at the Dazhi Cultural Center and uses a computational fluid dynamics (CFD) simulation to discuss the differences in wind velocity and ambient indoor temperature between all-zone air conditioning design and stratified air conditioning design. The results have strong implications for air conditioning design and can improve the indoor air quality of assembly halls.


2021 ◽  
Vol 2059 (1) ◽  
pp. 012003
Author(s):  
A Burmistrov ◽  
A Raykov ◽  
S Salikeev ◽  
E Kapustin

Abstract Numerical mathematical models of non-contact oil free scroll, Roots and screw vacuum pumps are developed. Modelling was carried out with the help of software CFD ANSYS-CFX and program TwinMesh for dynamic meshing. Pumping characteristics of non-contact pumps in viscous flow with the help of SST-turbulence model were calculated for varying rotors profiles, clearances, and rotating speeds. Comparison with experimental data verified adequacy of developed CFD models.


2021 ◽  
Vol 2053 (1) ◽  
pp. 012013
Author(s):  
N. Abdul Settar ◽  
S. Sarip ◽  
H.M. Kaidi

Abstract Wells turbine is an important component in the oscillating water column (OWC) system. Thus, many researchers tend to improve the performance via experiment or computational fluid dynamics (CFD) simulation, which is cheaper. As the CFD method becomes more popular, the lack of evidence to support the parameters used during the CFD simulation becomes a big issue. This paper aims to review the CFD models applied to the Wells turbine for the OWC system. Journal papers from the past ten years were summarized in brief critique. As a summary, the FLUENT and CFX software are mostly used to simulate the Wells turbine flow problems while SST k-ω turbulence model is the widely used model. A grid independence test is essential when doing CFD simulation. In conclusion, this review paper can show the research gap for CFD simulation and can reduce the time in selecting suitable parameters when involving simulation in the Wells turbine.


2014 ◽  
Vol 11 (6) ◽  
Author(s):  
Paolo Sala ◽  
Paola Gallo Stampino ◽  
Giovanni Dotelli

This work is part of a project whose final aim is the realization of an auxiliary power fuel cell generator. It was necessary to design and develop bipolar plates that would be suitable for this application. Bipolar plates have a relevant influence on the final performances of the entire device. A gas leakage or a bad management of the water produced during the reaction could be determinant during operations and would cause the failure of the stack. The development of the bipolar plates was performed in different steps. First, the necessity to make an esteem of the dynamics that happen inside the feeding channels led to perform analytical calculations. The values found were cross-checked performing a computational fluid dynamics (CFD) simulation; finally, it was defined the best pattern for the feeding channels, so that to enhance mass transport and achieve the best velocity profile. The bipolar plates designed were machined and assembled in a laboratory scale two cells prototype stack. Influences of the temperature and of the humidity were evaluated performing experiments at 60 deg and 70 deg and between 60% and 100% of humidity of the reactant gasses. The best operating point achieved in one of these conditions was improved by modifying the flow rates of the reactant, in order to obtain the highest output power, and it evaluated the reliability of the plates in experiments performed for longer times, at fixed voltages.


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