Performance prediction of steam ejector using computational fluid dynamics: Part 1. Validation of the CFD results

2007 ◽  
Vol 46 (8) ◽  
pp. 812-822 ◽  
Author(s):  
T. Sriveerakul ◽  
S. Aphornratana ◽  
K. Chunnanond
Author(s):  
Ernesto Benini ◽  
Giovanni Boscolo ◽  
Andrea Garavello

In spite of the remarkable advances in the field of the Computational Fluid Dynamics, algebraic models built upon empirical loss and deviation correlations are still one of the most reliable and effective tools to predict the performance of gas turbine stages with reasonable accuracy, especially when low-reaction, multi-stage architectures are considered. This paper deals with a comparison among some of the most popular loss correlations used by gas turbine manufacturers; such comparison is performed on a two-stage low-reaction turbine for which detailed experimental data are available. An overall assessment on the validity of loss correlations is carried out to help the designer/analyst using the most accurate model when both on- and off-design are to be carried out.


Author(s):  
P G Tucker ◽  
P S Keogh

The use of computational fluid dynamics (CFD) techniques enables performance predictions of bearing designs to be made when the usual operating assumptions of the Reynolds equation Jail to hold. This paper addresses the application of a full three-dimensional thermohydrodynamic CFD approach to journal bearings. The journal/shaft may extend beyond the bearing length and the rotation effect is accounted for in the thermal transport process. A circumferentially uniform shaft surface temperature is not assumed. Cavitation modelling is based on averaged lubricant/vapour properties and does not set pressures directly, allowing sub-ambient pressures to be predicted. Lubricant inlet grooves are incorporated with conservation of mass and the possibility of backflow. The modelling is validated against published experimental work on fully circumferential, single inlet and two-inlet circular bore bearings. The predicted and experimental results are in general agreement, although the predicted cyclic variation of journal surface temperature is less than the experimental value. However, an assumption in the predictions was of a non-orbiting journal. The techniques developed may, in principle, be extended to the orbiting journal case providing a dynamic cavitation model can be formulated.


2010 ◽  
Vol 97-101 ◽  
pp. 3463-3466
Author(s):  
Chun Lei Shao ◽  
Bo Qin Gu ◽  
X.L. Huang

Using Reynolds average N-S equations closed by standard k- turbulence model, the steady and unsteady turbulent flow in centrifugal pump was simulated by using MRF model and SM model respectively. A method for predicting the performances of centrifugal pump was built on the basis of computational fluid dynamics. By the presented performance prediction method, not only the flow characteristics of centrifugal pump can be obtained, but also can its performances be evaluated quantitatively and qualitatively. The advantages and disadvantages of some traditional design methods for centrifugal pump were analyzed. On the basis of performance prediction and flow analysis, a new design method was put forward in consideration of the steady and unsteady performances of centrifugal pump. The proposed method can be used to design the centrifugal pump with high running stability, efficiency and cavitation resistance, and it is available for shortening development period and improving design quality of pump.


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