Showing 6 results for A. R. Azimian
A. R. Azimian,
Volume 15, Issue 1 (7-1994)
Abstract
In this paper it is attempted to investigate the behavior of an inviscid flow in the meridional plane of an axial flow compressor. For this purpose the 3-D unsteady Euler equations in cylindrical coordinate are averaged in tangential direction. Therefore, the equations are reduced to a 2-D system. By averaging the tangential component of momentum equation, a blade force will result. Axial and radial components of the calculated blade force are added to the right hand side of the axial and radial momentum equation. By application of a 4th order Runge-Kutta time marching technique to the resulting 2-D Euler equations, the flow field is solved. Some interesting results are obtained which show the program capability in solving flow in the meridional plane of a compressor at the shortest possible time.
A. R. Azimian,
Volume 17, Issue 1 (7-1998)
Abstract
In this paper it is attempted to predict the off-design performance of a jet engine. After a review of the governing equations, the off-design performance is investigated by two methods. In the first method, the component characteristic curves of the Gas Turbines are used. In the second method some design point parameters and the reference state conditions are employed. The results obtained by this two methods fairly agree, and therefore, the second simple method which is independent of the component characteristics are recommended.
A. R. Azimian and S. Mohammadivand,
Volume 18, Issue 2 (7-1999)
Abstract
M. Goodarzi and A. R. Azimian,
Volume 22, Issue 2 (1-2004)
Abstract
For implementation
of the free surface boundary condition, a new subroutine has been introduced to an existing steady 3-D body fitted code. This code was previously written for steady flow simulation in closed ducts. The algorithm used in this subroutine reduces the instability problem according to the free surface wave generation. For code validation, it was applied to two different open channels. The results obtained for these test cases were compared with existing data. The comparison of the two sets of data was promising and proved that with this subroutine it is possible to predict the free surface position very well. The results of this routine were also compared with the symmetry boundary condition at the free surface for two mixing flows and it showed that, if the changes of the free surface elevation were small, the symmetry boundary condition could be considered as an accurate enough method
A. R. Azimian,
Volume 23, Issue 2 (1-2005)
Abstract
In this paper the laminar flow in the rectangular channel bends is simulated using numerical techniques. The turning angle of the channel bend and the area ratio of the channel cross-section are two important parameters to be examined. For flow simulation, the body fitted 3-D continuity and momentum equations are used and a body fitted general purpose code is developed. The existing results of a tied-diriven cavity and the experimental results from a 90 degree square bend were
used for code validation. After the code validation, the effect of the area change in the 90 degree bend is examined.
The numerical results indicated that increasing the area causes changes in the flow pattern, in turn, which has a direct impact on pressure drop. Similar results were obtained for other bend angles including 30, 60, 120, 150 and 180 degree bends. The results showed that increased bend turning angle increases the pressure drop which is in good agreement with existing experimental data.
A. R. Azimian,
Volume 24, Issue 1 (7-2005)
Abstract
Exergy analysis is based on combined first and second laws of thermodynamics and is a useful tool to analyze the energy systems in a better and more realistic way than an energy analysis, based on the first law of thermodynamics. Combination of exergy from thermodynamics with conventional concepts from engineering economy which is referred to as thermo-economy (exergo-economy) is a valuable tool to analyze the energy systems in a better way. In this paper, efforts are made to
apply the concept of thermo-economy to analyze two power cycles (a combined Gas and Steam cycle and a conventional steam power plant). In this analysis, the results of an exergy calculation are combined with the economic aspects such as investment costs, fuel costs, and also operation and maintenance costs. The goal of this study is to show how to implement the concept of thermo-economy to these cycles and also how to estimate the price of the product (electric power generated). Assessment of the components exergy destruction costs is a second objective in this study. Results obtained from this analysis clearly show the effect of the cost breakdown and the component performance on the price of the final product. Comparison of the price of the product in these cycles shows that the combined cycle is superior to the conventional steam power plant.
