Abstract
A mathematical model was developed for the drying of paper in a multi-cylinder drying section. The model is based on the unsteady state, one-dimensional heat conduction equation, which is applied to both the cylinder shell and the paper web. No internal mass transfer phenomena were modelled explicitly. A lumped parameter, the effective thermal conductivity of the paper, implicitly takes these phenomena at least partially into account. Great emphasis was placed on finding the proper heat and mass transfer coefficients that are a part of the boundary conditions of the unsteady state heat conduction equation. Three of these boundary conditions were investigated in detail: * contact heat transfer at the cylinder-paper interface was studied experimentally, * mass transfer at the paper-fabric-air interfaces was also investigated experimentally, and * laminar condensate flow inside the cylinders was studied using a computational fluid dynamics program. Based on the mathematical model, a simulation program was developed. The data predicted by the program compared favorably with measured data from nine different industrial paper dryers. The model applied just as well as lighter paper grades such as newsprint as to heavier grades such as paper board. Two parameters were used to tune the output of the program
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Citation Formats
Wilhelmsson, B.
An experimental and theoretical study of multi-cylinder paper drying.
Sweden: N. p.,
1995.
Web.
Wilhelmsson, B.
An experimental and theoretical study of multi-cylinder paper drying.
Sweden.
Wilhelmsson, B.
1995.
"An experimental and theoretical study of multi-cylinder paper drying."
Sweden.
@misc{etde_10114489,
title = {An experimental and theoretical study of multi-cylinder paper drying}
author = {Wilhelmsson, B}
abstractNote = {A mathematical model was developed for the drying of paper in a multi-cylinder drying section. The model is based on the unsteady state, one-dimensional heat conduction equation, which is applied to both the cylinder shell and the paper web. No internal mass transfer phenomena were modelled explicitly. A lumped parameter, the effective thermal conductivity of the paper, implicitly takes these phenomena at least partially into account. Great emphasis was placed on finding the proper heat and mass transfer coefficients that are a part of the boundary conditions of the unsteady state heat conduction equation. Three of these boundary conditions were investigated in detail: * contact heat transfer at the cylinder-paper interface was studied experimentally, * mass transfer at the paper-fabric-air interfaces was also investigated experimentally, and * laminar condensate flow inside the cylinders was studied using a computational fluid dynamics program. Based on the mathematical model, a simulation program was developed. The data predicted by the program compared favorably with measured data from nine different industrial paper dryers. The model applied just as well as lighter paper grades such as newsprint as to heavier grades such as paper board. Two parameters were used to tune the output of the program to the values measured. Both parameters were assigned physically reasonable values confined to a rather narrow range. Studies of the effect of certain input data of the program were also performed. These indicated, for example, that the condensate coefficient and the contact coefficient were the most influential of the heat transfer coefficients, but that the mass transfer coefficient of the dryer fabric was of only slight influence. The potential for simulating different operating conditions was illustrated by several examples. 113 refs}
place = {Sweden}
year = {1995}
month = {Jan}
}
title = {An experimental and theoretical study of multi-cylinder paper drying}
author = {Wilhelmsson, B}
abstractNote = {A mathematical model was developed for the drying of paper in a multi-cylinder drying section. The model is based on the unsteady state, one-dimensional heat conduction equation, which is applied to both the cylinder shell and the paper web. No internal mass transfer phenomena were modelled explicitly. A lumped parameter, the effective thermal conductivity of the paper, implicitly takes these phenomena at least partially into account. Great emphasis was placed on finding the proper heat and mass transfer coefficients that are a part of the boundary conditions of the unsteady state heat conduction equation. Three of these boundary conditions were investigated in detail: * contact heat transfer at the cylinder-paper interface was studied experimentally, * mass transfer at the paper-fabric-air interfaces was also investigated experimentally, and * laminar condensate flow inside the cylinders was studied using a computational fluid dynamics program. Based on the mathematical model, a simulation program was developed. The data predicted by the program compared favorably with measured data from nine different industrial paper dryers. The model applied just as well as lighter paper grades such as newsprint as to heavier grades such as paper board. Two parameters were used to tune the output of the program to the values measured. Both parameters were assigned physically reasonable values confined to a rather narrow range. Studies of the effect of certain input data of the program were also performed. These indicated, for example, that the condensate coefficient and the contact coefficient were the most influential of the heat transfer coefficients, but that the mass transfer coefficient of the dryer fabric was of only slight influence. The potential for simulating different operating conditions was illustrated by several examples. 113 refs}
place = {Sweden}
year = {1995}
month = {Jan}
}