DOI: 10.1615/ICHMT.1986.AdvCourseHighTempEq
ISBN Print: 978-0-89116-568-2
Calculation of High Temperature Regenerative Heat Exchangers
要約
Regenerative heat exchangers are used in a variety of industrial processes and in a number of configurations. These applications are outlined and methods of calculating the thermal performance of regenerators are described. As an introduction to the problem, the calculation of the temperature distribution with a single blow of fluid through a porous solid packing is described. This leads to the concept of a modified or lumped heat transfer coefficient to allow for the variation in temperature through the thickness of the solid. The full regenerator problem is then formulated as a series of single blow problems. For the case where the main physical parameters are constant, it is shown that the problem can be characterised by dimensionless or reduced parameters. The effect of non-linearities, due to the temperature dependence of physical properties, radiative heat transfer at high temperatures, etc., are also considered.
Hausen's method for relating the performance of a regenerator to that of an equivalent recuperator is presented, this providing a very useful technique for estimating the performance of a simple regenerator. Numerical techniques for obtaining the temperature distributions are also described. Closed numerical methods to determine the steady state distribution directly are outlined, and open techniques based on a finite difference approach are described in more detail, together with a discussion of strongly non-linear problems. Finally, some results from analysis of the transient performance of regenerators are presented.