Void Fractions in Subcooled Flow Boiling

1969 ◽  
Vol 91 (4) ◽  
pp. 471-476 ◽  
Author(s):  
P. S. Larsen ◽  
L. S. Tong
Keyword(s):  
Heat Transfer ◽  
Flow Boiling ◽  
Heated Surface ◽  
Liquid Core ◽  
Heat Removal ◽  
Two Phase ◽  
Subcooled Flow Boiling ◽  
Void Fractions ◽  
Subcooled Flow ◽  
The Difference

A semianalytic model is presented for the prediction of void fractions in subcooled flow boiling at elevated pressures. The model is based on the formation and growth of a bubble boundary layer adjacent to the heated surface at a rate determined by the difference between the imposed surface heat transfer and the heat removal capability of the subcooled liquid core of the flow. The latter heat transfer rate is determined by the analogy between heat and momentum transfer in the liquid employing empirical friction-factor data for low-quality two-phase flow. The analysis is compared to experimental results.

Investigations on Effect of Lift and Wall Lubrication Forces on the Subcooled Flow Boiling

2020 ◽  
Vol 6 (4) ◽  
Author(s):  
Sai Raja Gopal Vadlamudi ◽  
Arun K. Nayak
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flow Boiling ◽  
Nucleate Boiling ◽  
Eulerian Model ◽  
Subcooled Flow Boiling ◽  
Void Fractions ◽  
Subcooled Flow ◽  
Flux Partitioning ◽  
The Impact

Abstract Subcooled flow boiling is widely used as a mode of heat transfer in many industries, especially in nuclear reactors. Despite its advantages, the heat transfer is hampered beyond a certain flux due to a phenomenon known as departure from nucleate boiling (DNB). It is important to determine the void fraction profiles, especially the near-wall void fractions, to evaluate the limiting heat flux conditions. The two-fluid Eulerian model, coupled with the heat flux partitioning model, is widely used to predict subcooled flow boiling characteristics. Over the years, many researchers have not considered lift and wall lubrication forces in their modeling of subcooled flow boiling. Few researchers have considered the Tomiyama model for lift force; however, their results were not encouraging. Moreover, there is no systematic study in evaluating the impact of lift and wall lubrication forces on subcooled flow boiling. In this paper, various lift and wall lubrication models are compared to understand the implications of these forces on void distribution. The advantages and limitations of the models are discussed in detail.

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