关于热力学、热量传递和质量传递,以及流体工程的 A-Z 指南
中文 English Русский Português Español Français Deutsch 关于我们 编辑 联系我们 访问 Begell House
View in A-Z Index

The boiling number is dimensionless group involving the heat flux , defined by Bg = . It can be thought of as a ratio mass flow rates per unit area, (/hLG)/, i.e.,

This dimensionless group was used by Davidson et al. in 1943. They argued that it represented the stirring effect of the bubbles upon the flow. Later, the group was named the boiling number.

The boiling number is used in convective boiling. Shah (1982) uses an empirical boiling number correction to the single-phase liquid heat transfer coefficient in order to predict the two-phase heat transfer. This approach avoids the introduction of a nucleate pool boiling term into the correlation.

Another application is in modeling the critical heat flux. Measurements of critical heat flux can be expressed in dimensionless form, which, to a first approximation is valid for all fluids, if they are put in the form of a boiling number, i.e., Bgcrit = . Tables can then be constructed of Bgcrit in terms of other dimensionless groups (e.g., ESDU, 1986).

REFERENCES

Davidson, W. F. et al. (1943) Studies of heat transmission through boiler tubing at pressures from 500 to 3300 pounds, ASME Trans. 65:553–579.

ESDU Data Item 86032. (1986) Boiling Inside Tubes: Critical Heat Flux for Upward Flow in Uniformly-Heated Vertical Tubes.

Shah, M. M. (1982) Chart correlation for saturated boiling heat transfer: equations and further study, ASHRAE Trans. 88:185–196.

References

  1. Davidson, W. F. et al. (1943) Studies of heat transmission through boiler tubing at pressures from 500 to 3300 pounds, ASME Trans. 65:553–579.
  2. ESDU Data Item 86032. (1986) Boiling Inside Tubes: Critical Heat Flux for Upward Flow in Uniformly-Heated Vertical Tubes.
  3. Shah, M. M. (1982) Chart correlation for saturated boiling heat transfer: equations and further study, ASHRAE Trans. 88:185–196.
浏览次数: 30822 创建日期: 2 February 2011 最后修改日期: 10 February 2011 © Copyright 2010-2021 返回顶部
A-Z 索引 作者/编辑 语义地图 视觉画廊 贡献 Guest