A numerical study of bubble growth during low pressure structural foam molding process

1990 ◽  
Vol 30 (20) ◽  
pp. 1330-1337 ◽  
Author(s):  
A. Arefmanesh ◽  
S. G. Advani ◽  
E. E. Michaelides
Keyword(s):  
Bubble Growth ◽  
Numerical Study ◽  
Low Pressure ◽  
Molding Process ◽  
Structural Foam

Detailed Numerical Study of the Main Sources of Loss and Flow Behavior in Low Pressure Steam Turbine Exhaust Hoods

2017 ◽  
Author(s):  
Dickson Munyoki ◽  
Markus Schatz ◽  
Damian M. Vogt
Keyword(s):  
Steam Turbine ◽  
Numerical Study ◽  
Flow Behavior ◽  
Low Pressure ◽  
Operating Conditions ◽  
Pressure Recovery ◽  
Exhaust Hood ◽  
Recovery Coefficient ◽  
Pressure Steam ◽  
Underlying Mechanisms

The performance of the axial-radial diffuser downstream of the last low-pressure steam turbine stages and the losses occurring subsequently within the exhaust hood directly influences the overall efficiency of a steam power plant. It is estimated that an improvement of the pressure recovery in the diffuser and exhaust hood by 10% translates into 1% of last stage efficiency [11]. While the design of axial-radial diffusers has been the object of quite many studies, the flow phenomena occurring within the exhaust hood have not received much attention in recent years. However, major losses occur due to dissipation within vortices and inability of the hood to properly diffuse the flow. Flow turning from radial to downward flow towards the condenser, especially at the upper part of the hood is essentially the main cause for this. This paper presents a detailed analysis of the losses within the exhaust hood flow for two operating conditions based on numerical results. In order to identify the underlying mechanisms and the locations where dissipation mainly occurs, an approach was followed, whereby the diffuser inflow is divided into different sectors and pressure recovery, dissipation and finally residual kinetic energy of the flow originating from these sectors is calculated at different locations within the hood. Based on this method, the flow from the topmost sectors at the diffuser inlet is found to cause the highest dissipation for both investigated cases. Upon hitting the exhaust hood walls, the flow on the upper part of the diffuser is deflected, forming complex vortices which are stretching into the condenser and interacting with flow originating from other sectors, thereby causing further swirling and generating additional losses. The detailed study of the flow behavior in the exhaust hood and the associated dissipation presents an opportunity for future investigations of efficient geometrical features to be introduced within the hood to improve the flow and hence the overall pressure recovery coefficient.

Numerical study of bubble growth and merger characteristics during nucleate boiling

2019 ◽  
Vol 112 ◽  
pp. 7-19
Author(s):  
Jingliang Bi ◽  
David M. Christopher ◽  
Dawei Zhao ◽  
Jianjun Xu ◽  
Yanping Huang
Keyword(s):  
Bubble Growth ◽  
Numerical Study ◽  
Nucleate Boiling

Experimental and Numerical Study of Ethyl Valerate Flat Flames at Low Pressure

2017 ◽  
Vol 190 (4) ◽  
pp. 632-662 ◽  
Author(s):  
Haddy Mbuyi Katshiatshia ◽  
Véronique Dias ◽  
Hervé Jeanmart
Keyword(s):  
Numerical Study ◽  
Low Pressure
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