Determination of shell-side heat transfer coefficients by the naphthalene sublimation technique

Experiments are described in which shell-side heat transfer coefficients for a shell-and-tube heat exchanger were determined from mass transfer measurements. The mass transfer experiments were carried out using the naphthalene sublimation technique. In utilizing the technique, the external surface of the tubes is coated with a film of naphthalene, which sublimes when exposed to an air flow. Mass transfer coefficients were measured for fully developed flow conditions at each of the tubes in the cross section. These coefficients were transformed to heat transfer coefficients by employing the analogy between heat and mass transfer. Detailed pressure drop measurements were made internal to the heat exchanger, and the axial pressure distribution indicated that the fluid flow was fully developed downstream of the first compartment. The cross-sectionally averaged mass (heat) transfer coefficients and the pressure drop were compared with the predictions from two well-established methods for the thermal-hydraulic design of shell-and-tube heat exchangers.