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This paper presents the results of calculations of the shell-side heat transfer coefficient and pressure drop for a shell-and-tube heat exchanger with an inner shell diameter of 200.2 mm and an effective tube length of 518 mm. The exchanger contained 85 copper tubes (12/10 mm), arranged in a staggered layout with a pitch ratio of 1.5. It was equipped with nine segmental baffles, with a 25% baffle cut and a baffle spacing of 48 mm. The inlet temperature of the hot water flowing through the shell, and the mass flow rate, were varied in the ranges of 35–79 °C and 1–3 kg/s, respectively. The calculations were performed using the extended Bell–Delaware method, the VDI (Gaddis–Gnielinski) method, and the Aspen Exchanger Design and Rating. CFD simulations were performed using the OpenFOAM and Ansys Fluent software packages. The calculated results were then compared with the available experimental data. The findings showed that the VDI method generated the greatest overestimation of the heat transfer coefficient and underestimated the pressure drop, whereas the extended Bell–Delaware method demonstrated the highest agreement with the experimental data.

The paper presents the results of research on liquid flow maldistribution in the shell side of a shell-and-tube heat exchanger (STHE). This phenomenon constitutes the reason for the formation of the velocity reduction area and adversely affects heat transfer and pressure drop. In order to provide details of the liquid distribution in STHE, two visualization methods were utilized. First, computational fluid dynamics (CFD) code coupled with the k-ε model and the laser-based particle image velocimetry (PIV) technique was applied. The tests were carried out for a bundle comprising 37 tubes in an in-line layout with a pitch dz/t = 1.5, placed in a shell with Din = 0.1 m. The STHE liquid feed rates corresponded to Reynolds numbers Rein equal to 16,662, 24,993, and 33,324. The analysis demonstrated that the flow maldistribution in the investigated geometry originates the result of three main streams in the cross-section of the shell side: central stream, oblique stream, and bypass stream. For central and oblique streams, the largest velocity reduction areas were formed in the wake of the tubes. On the basis of the flow visualization, it was also shown that the in-line layout of the tube bundle helps to boost the wake region between successive tubes in a row. Additionally, unfavorable vortex phenomena between the last row of tubes and the lower part of the exchanger shell were identified in the investigations. The conducted studies confirmed the feasibility of both methods in the identification and assessment of fluid flow irregularities in STHE. The maximum error of the CFD method in comparison to the experimental methods did not exceed 7% in terms of the pressure drops and 11% in the range of the maximum velocities.

The liquefied natural gas (LNG) floating production storage and offloading (FPSO) unit is a new type of floating production device developed for the exploitation, pretreatment, liquefaction, and storage of offshore natural gas. In this study, the shell side structure of the spiral-wound heat exchanger is analyzed, and the effects of varying the Reynolds number (Re), tube outer diameter, and number of distributors on the thickness of the shell-side liquid film are investigated. The results show that as the fluid flows down from the distributor, it hits the upper wall of the pipeline and diffuses evenly to both sides, before converging in between the two distributors. In the axial direction, the thickness of the liquid film increases first, reaches the highest at the peak, then decreases, reaches the lowest at the trough, and then increases again, forming a secondary peak at the drop. The thickness of the liquid film changes periodically, and the period is the distance between the two distributors. The thickness of the circumferential liquid film is negatively correlated with the circumferential angle, α. Moreover, the liquid film is thinnest at α = 120°, and is positively correlated with both the liquid mass flow rate and the outer diameter of the tube. The most uniform liquid film thickness is obtained when Re = 1500, the tube outer diameter is 12 mm, and the number of distributors is 6. The results from this study can guide the design of spiral-wound heat exchangers and facilitate their safe and efficient operation in natural gas liquefaction processes.

The Helically Coiled Heat Exchanger (HCHX) is a promising candidate for modular Molten Salt Reactors (MSRs), valued for its high heat transfer efficiency, structural compactness, reduced fouling tendency, and excellent thermal compensation capabilities. The thermal–hydraulic performance of the shell side, crucial for reactor efficiency and safety, requires accurate prediction. This is challenged by the scarcity of reliable correlations for high-Prandtl number fluoride salts under low-Reynolds number conditions. To address this gap, this study explores the heat transfer and flow resistance of FNaBe salt flow in an HCHX using Computational Fluid Dynamics (CFD). The validated CFD model examines the effects of structural parameters (number of layers, tube pitch, and helix angle) and inlet conditions (temperatures and velocities). It is found that the Nusselt number and friction factor increase with more layers but decrease with a higher tube pitch and helix angle. Subsequently, new empirical correlations integrating these geometric parameters are proposed, demonstrating excellent agreement with simulation results (deviations within the range of −10–5% for Nu and −5–10% for f). This study offers vital theoretical support for optimizing compact HCHX designs in MSRs.

Reliable mathematical models are important tools for design/optimization of haemo-filtration modules. For a specific module, such a model requires knowledge of fluid- mechanical and mass transfer parameters, which have to be determined through experimental data representative of the usual countercurrent operation. Attempting to determine all these parameters, through measured/external flow-rates and pressures, combined with the inherent inaccuracies of pressure measurements, creates an ill-posed problem (as recently shown). The novel systematic methodology followed herein, demonstrated for Newtonian fluids, involves specially designed experiments, allowing first the independent reliable determination of fluid-mechanical parameters. In this paper, the method is further developed, to determine the complete mass transfer module-characteristics; i.e., the mass transfer problem is modelled/solved, employing the already fully-described flow field. Furthermore, the model is validated using new/detailed experimental data on concentration profiles of a typical solute (urea) in counter-current flow. A single intrinsic-parameter value (i.e., the unknown effective solute-diffusivity in the membrane) satisfactorily fits all data. Significant insights are also obtained regarding the relative contributions of convective and diffusive mass-transfer. This study completes the method for reliable module simulation in Newtonian-liquid flow and provides the basis for extension to plasma/blood haemofiltration, where account should be also taken of oncotic-pressure and membrane-fouling effects.

The calculation of the heat transfer coefficients is made dependent on the Reynolds and the Prandtl number. The heat transfer coefficient in the tubes is dependent on the flow velocity and the tube diameter. On the shell side, the flow velocity can be increased with smaller baffle spacing. This improves the heat transfer. With bypass streams the shell-side heat transfer coefficient can be considerably deteriorated. In floating head heat exchangers, the sealing strips should be installed in order to reduce the product streams between the shell and the tube bundle. Comparison of different calculation models shows that the deviations in the calculated overall heat transfer coefficients are small. Finally, it is shown how to calculate the pressure losses at the tube and shell side and how to design a heat exchanger for a given problem definition easily and quickly with the help of heat exchanger tables.

The full Delaware method for shell-side heat transfer and pressure drop calculations is presented in this chapter. Ideal tube bank correlations for heat-transfer coefficients and friction factors are presented and corrections for the effects of leakage and bypass flows on heat transfer and pressure drop are discussed. Methods are given for computing correction factors and the leakage and bypass flow areas on which they are based. Methods for estimating shell-side clearances that give rise to leakage flows are presented. The entire procedure is illustrated through an example that is worked in detail. The results are compared with those obtained previously using HEXTRAN and the Simplified Delaware method.

Limited by manufacturing technology, there have to be a central tube designed at the center shaft position of CHBSTHX. In this paper, the influence of dimension of central tube on the shell-side performance of the heat exchanger is investigated by means of CFD. Research presents that the pressure drop is greater in central area than that in perimeter zone; the dimension of central tube influences heat transfer and pressure drop limitedly, similar fluid condition provides similar shell-side performance of heat transfer and pressure drop respectively regardless of the dimension of central tube; larger dimension of central tube brings greater drop of the integrated performance of heat exchanger, in the designed dimension, about 3%~4% of integrated performance drop follows the dimension of the central tube increases step by step.

The method for determining the flow cross sections and the flow velocities at the tube side and the shell side are shown. How many tubes are required for a certain flow velocity or Reynolds number? How to determine the flow velocity for the cross and longitudinal streams at the shell side? What baffle spacing is required for a specific flow velocity? How many tube rows must be streamed?

Numerical simulation of shell-and-tube heat exchangers with novel helical baffles was carried out by using commercial codes to study shell-side flow and heat transfer characteristics. The results show that compared with shell-and-tube heat exchangers with conventional helical baffles, the ones with novel helical baffles can efficiently reduce the leakage from triangle zone so that the distributions of both the velocity field and heat transfer on tubes are more uniform. The comparison of comprehensive performance which is evaluated by heat transfer coefficient per unit pressure drop between conventional helical baffles and novel ones indicates that the latter performs better.