Abstract

This paper describes a three-dimensional numerical model for simulation of turbulent flow and heat transfer inside shell-and-tube heat exchangers. A SIMPLE (Patankar and Spalding, 1972) type solution algorithm is used on a colocated grid. The simulation of shell-and-tube heat exchangers is based on a distributed resistance method that uses a modified two equation k-ε turbulence model. Volume porosities and non-homogeneous surface permeabilities account for tubes, nozzles, and an arbitrary arrangement of baffles. Sub-models are used for shellside pressure drop by tubes, turbulence generation and dissipation by tubes, baffle-shell and baffle-tube leakage, shellside and tubeside heat transfer. These sub-models use parameters that have not been altered from their published values. The details of the sub-models are described in detail by Prithiviraj and Andrews (1995, 1996).

The numerical model was validated by comparison with experimental data for shell-and-tube heat exchangers from University of Delaware (Bell, 1963) and Argonne National Labs (Halle et al., 1984) by Prithiviraj and Andrews (1996). Good agreement was obtained between the computations and experiments. This paper uses the model to simulate flow and heat transfer in Full Bundle and No Tubes In The Window (NTIW) bundle types (In the NTIW design, tubes in the window region are removed). The effect of shell type and bundle type on the pressure drop and heat transfer is examined. The performance of the numerical model is compared with the methods of Bell (1981), Kern (1950), and Donohue (1949), for a range of shellside Reynolds numbers. It is shown that at the price of an increased computation cost, the three-dimensional numerical model yields better predictions than the above methods, along with detailed flow, turbulence, and temperature fields.

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