Atkinson, Bruce J; Stephens, Darrin W; Harris, Jonathan A; Schneider, Phil A The net pressure driving force due to boiling in calandria tubes. Inproceedings Hogarth, DM (Ed.): Australian Society of Sugar Cane Technologists, 2000. Abstract | Links | BibTeX | Tags: Boiling, Calandria, Evaporation, Flow, Mass Flow Rate, Model, Pressure, Temperature, Thermodynamic, Two-Phase, Vacuum Pan @inproceedings{atkinson2000net,
title = {The net pressure driving force due to boiling in calandria tubes.},
author = {Bruce J Atkinson and Darrin W Stephens and Jonathan A Harris and Phil A Schneider},
editor = {DM Hogarth },
doi = {10.13140/RG.2.1.1998.5762},
year = {2000},
date = {2000-01-01},
booktitle = {Australian Society of Sugar Cane Technologists},
journal = {Proceedings of the 2000 Conference of the Australian Society of Sugar Cane Technologists held at Bundaberg, Queensland, Australia, 2 May to 5 May 2000.},
volume = {22},
abstract = {Vapour formation due to boiling in calandria tubes provides the driving force for natural circulation in vacuums pans. The net pressure difference generated across a calandria tube is determined by the average density deficit in the tube relative to the downcomer (i.e. the amount of vapour in the tube) and the pressure loss due to friction and acceleration. This paper presents a mathematical model of the two-phase flow of molasses and vapour in calandria tube assuming equilibrium thermodynamics and steady state conditions. The model can predict the net pressure driving force and the evaporation rate produced by a tube as a function of parameters such as heat input, mass flow rate, liquid height above the calandria and boiling point elevation. Additionally, the model yields detailed profiles of temperature, absolute pressure, volume fraction and other variables as a function of distance along the calandria tube. Results are presented in the form of characteristic curves representing the net pressure difference available to drive natural circulation as a function of applied heat and mass flow rate. The circulation rate and evaporation rate in natural circulation lop may be determined by matching the appropriate characteristic curve to the system response curve for the loop. An example is presented to illustrate the application of the model.},
keywords = {Boiling, Calandria, Evaporation, Flow, Mass Flow Rate, Model, Pressure, Temperature, Thermodynamic, Two-Phase, Vacuum Pan},
pubstate = {published},
tppubtype = {inproceedings}
}
Vapour formation due to boiling in calandria tubes provides the driving force for natural circulation in vacuums pans. The net pressure difference generated across a calandria tube is determined by the average density deficit in the tube relative to the downcomer (i.e. the amount of vapour in the tube) and the pressure loss due to friction and acceleration. This paper presents a mathematical model of the two-phase flow of molasses and vapour in calandria tube assuming equilibrium thermodynamics and steady state conditions. The model can predict the net pressure driving force and the evaporation rate produced by a tube as a function of parameters such as heat input, mass flow rate, liquid height above the calandria and boiling point elevation. Additionally, the model yields detailed profiles of temperature, absolute pressure, volume fraction and other variables as a function of distance along the calandria tube. Results are presented in the form of characteristic curves representing the net pressure difference available to drive natural circulation as a function of applied heat and mass flow rate. The circulation rate and evaporation rate in natural circulation lop may be determined by matching the appropriate characteristic curve to the system response curve for the loop. An example is presented to illustrate the application of the model. |