Flow maldistribution and heat transfer characteristics in plate and shell heat exchangers

Abstract

• The pressure drop, flow maldistribution, and heat transfer rate are measured in a plate and shell heat exchanger. • Friction factor and Nusselt number correlations are provided for water and oil flows. • The plate side showed a better thermal performance than the shell side but a higher friction factor. • Flow maldistribution was more severe on the shell side than on the plate side. • The effectiveness deterioration due to the flow maldistribution was less than 4%. • An analytical comparison indicates that PHEs have a better thermo-hydraulic performance than the PSHE studied. The plate and shell heat exchanger (PSHE) was developed to overcome the traditional gasketed plate heat exchangers (PHE) operation limits. Its constructive characteristics allow higher-pressure and thermal applications, suitable for processes found in power plants and the oil and gas industry. However, studies on the PSHE thermo-hydraulic performance are still scarce. This study presents an experimental and theoretical analysis of the flow and heat transfer characteristics of a PSHE. A test rig operates with water and viscous oil to produce turbulent and laminar flow regimes, typical of the oil and gas industry. The heat transfer rate, pressure drop, and flow distribution are measured. The m 2 -model, developed to predict flow maldistribution on the PHE, is suitable for the plate side of the PSHE. An analytical model is used to correct the effects of maldistribution on the overall heat transfer coefficient and provide Nusselt number correlations. Experiments show that the flow maldistribution increases the heat exchanger pressure drop and deteriorates the heat transfer performance. The maximum and average channel flow rate ratio reaches 2.30 on the shell side and 1.75 on the plate side. Friction factor correlations are created based on the channel pressure drop data. The shell side has an inferior overall performance than the plate side, with a higher maldistribution and a lower Nusselt number. The PSHE effectiveness deterioration due to the maldistribution is 4% in the worst scenario within the experimental range. Results indicate that the PHE thermo-hydraulic performance is superior to the PSHE. Nevertheless, the structural advantages of the PSHE make it appropriate for applications involving high pressures and elevated temperatures.