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The main purpose of this paper is the generation of the heat transfer and pressure drop correlations by considering three working fluids, namely air, water, and ethylene glycol, for the wavy plate-fin heat exchangers (PFHEs).

In order to present the general correlations, various models with different geometrical parameters should be tested. Because of the problems, such as difficult, long time, and costly fabrication of the wavy fins in experimental tests, computational fluid dynamics (CFD) calculations can be a useful method for the generation of the heat transfer and pressure drop correlations with eliminating the experimental problems. Hence, the effective design parameters of the wavy plate-fin, including fin pitch, fin height, wave length, fin thickness, wave amplitude, and fin length, and also their levels were recognized from the literature. The Taguchi method was applied to formulate the CFD simulation work.

The simulation results were compared and validated with an available experimental data. The mean deviations of the Colburn factor, j, and Fanning friction factor, f, values between the simulation results and the experimental data were 3.74 and 9.07 percent, respectively. The presented air correlations and experimental data were in a good agreement, so that approximately 95 percent of the experimental data were correlated within ±12 percent. The j factor values varied for the different working fluids, while the f factor values did not sensibly change.

The presented correlations can be used to estimate the thermal-hydraulic characteristics and to design of the compact PFHE with the wavy channels.

This manuscript presents the new correlations for the compact PFHEs with the way channels by considering all the geometrical parameters and the working fluids with the different Prandtl numbers, 0.7, 7, and 150.

The purpose of this paper is to carry out numerical modeling of single-blow transient analysis using FLUENT porous media model for estimation of heat transfer and pressure drop characteristics of offset and wavy fins.

A computational fluid dynamics program FLUENT has been used to predict the design data in terms of j and f factors for plate-fin heat exchanger wavy and offset strip fins, which are widely used in aerospace applications.

The suitable design data in terms of Colburn j and Fanning friction f factors is generated and presented correlations for wavy fins covering the laminar, transition and turbulent flow regimes.

The correlations for the friction factor f and Colburn factor j have been found to be good by comparing with other references. The correlations can be used by the heat exchanger designers and can reduce the number of tests and modification of the prototype to a minimum for similar applications and types of fins.

In this paper three‐dimensional numerical simulations were conducted for the periodically developed laminar flow in the sinusoid wavy fin‐and‐tube heat exchanger.

A novel CLEARER algorithm is adopted to guarantee the fully coupling between the pressure and velocity, and it can not only speed up the convergence rate, but also overcome the severe grid non‐orthogonality in the wavy fin‐and‐tube heat exchanger. The influence of wave amplitude, fin pitch, tube diameter and wave density on fluid flow and heat transfer characteristics is analyzed under different Reynolds numbers.

The numerical results show that with the increase of wave amplitude, tube diameter or wave density, both the friction factor and Nusselt number will increase, and the increase rate of friction factor is higher than that of Nusselt number. It is interesting to note that, at low Reynolds numbers the Nusselt number increases with the decrease of fin pitch, while at high Reynolds numbers, the Nusselt number increases with the increase of fin pitch.

The numerical results presented in this paper may provide some useful guidance in the design of the wavy fin‐and‐tube heat exchanger with large number of rows of tubes.

In aerospace applications, due to the severe limitations on the weight and space envelope, it is mandatory to use high performance compact heat exchangers (CHEs) for enhancing the heat transfer rate. The most popularly used ones in CHEs are the plain fins, offset strip fins (OSFs), louvered fins and wavy fins. Amongst these fin types, wavy and offset fins assume a lot of importance due to their enhanced thermo‐hydraulic performance. The purpose of this paper is to investigate the influence of geometrical fin parameters, in addition to Reynolds number, on the thermo‐hydraulic performance of OSFs.

A computational fluid dynamics approach is used to conduct a number of numerical experiments for determination of thermo‐hydraulic performance of OSFs considering the various geometrical parameters, which are generally used in the aerospace industry. These investigations include the study of flow pattern for laminar, transition and turbulent regions. Studies are conducted with different fin geometries and comparisons are made with available data in open literature. Finally, the generalized correlations are developed for OSFs taking all geometrical parameters into account for the entire range of operations of the aerospace industry covering laminar, transition and turbulent regions. In addition, the effects of various geometrical parameters are presented as parametric studies.

Thermo‐hydraulic design of CHEs is strongly dependent upon the predicted/measured dimensionless performance (Colburn factor “j” and Fanning friction “f” vs Reynolds number Re) of heat transfer surfaces. Several types of OSFs used in the compact plate‐fin heat exchangers are analyzed numerically.

The present numerical analysis is carried out for “air” media and hence these results may not be accurate for other fluids with large variations of Prandtl numbers.

In open literature, these fins are generally evaluated as a function of Reynolds number experimentally, which are expensive. However, their performance will also depend to some extent on geometrical parameters such as fin thickness, fin spacing, offset fin length and fin height.

This numerical estimation can reduce the number of tests/experiments to a minimum for similar applications.

To provide some heat transfer and friction factor results for fin‐and‐tube heat transfer surfaces which may be used in air conditioning industry.

Numerical simulation approach was adopted to compare the plain plate fin and three types of radial slotted fin surfaces.

It is found that at the same frontal velocity (1.0‐3 m/s) the plain plate fin has the lowest heat transfer rate with the smallest pressure drop. The full slotted fin surface has the highest heat transfer rate with the largest pressure drop penalty. The partially slotted fin (where the strips are mainly located in the rear part of the fin) and the back slotted fin are some what in between. Under the identical pumping power constraint, the partially slotted fin surface behaves the best.

The results are only valid the two‐row fin surface.

The results are very useful for the design of two‐row tube fin surfaces with high efficiency.

This paper provides original information of slotted fin surface with radial strips from the field synergy principle.

The purpose of this paper is to investigate thermohydraulic characteristics of turbulent flow of water (4,000 = Re = 10,000) in a rectangular channel equipped with perforated chevron plat-fin (PCPF) with different vortex generators (VGs) shapes.

First, three general shapes of VGs including rectangular, triangular and half circle, are compared to each other. Then, the various shapes of rectangular VGs, (horizontal, vertical and square) and triangular VGs, (forward, backward and symmetric) are evaluated. To comprehensively evaluate the thermohydraulic performance of the PCPF with various VG shapes, the relationship between the Colburn factor and the friction factor (j/f) is presented, then a performance index (η) is applied using these factors.

Results show that the enhanced models of the PCPF, which are equipped with VGs, have higher values of j/f ratio and η as compared with the reference model (R). Further, the half-circle VG with the lowest pressure drop values (about 2.4% and 4.9%, averagely as compared with the S and ST vortex generators), shows the highest thermohydraulic performance among the proposed shapes. The maximum of performance index of 1.14 is found for the HC vortex generator at Re = 4,000. It is also found that the square and forward triangular VGs, have the best thermohydraulic performance among the rectangular and triangular VGs respectively and the highest performance index of 1.13 and 1.11 are reported for these VGs.

The thermohydraulic performance of the PCPF with different vortex generators VGs shapes have been investigated.

Heat transfer inside wavy fins is analyzed in this work. The paper aim to discuss this issue.

Six different types of wavy fins are considered. The fin equation for each fin type is solved using a high accurate finite difference method. Excellent agreement is obtained between the numerical solution under zero wave amplitude and the exact solution of the plain fin.

The following wavy fin types and conditions are found to produce larger heat transfer rate and its volumetric value than those for the plain fin and other wavy fins: short fins with parallel wavy profiles and large surface-wave frequency; long fins with symmetric wavy surface around the length axis, positive cross-sectional area gradient at the base, and large surface-wave frequency; and long fins with symmetric wavy profiles around the length axis, positive cross-sectional area gradient at the base, and small surface-wave frequency.

In addition, both fins with symmetric wavy surface around the width axis and parallel wavy surfaces along the width axis have same performance indicators. Also, these wavy fins possess higher fin efficiency than either that of the plain fin or those of the other types of wavy fins.

Finally, heat transfer enhancements in the studied wavy fins are increased by increases in the excess of the surface area, cross-sectional area gradient at the base, arc length and arc width relative to those of the plain fin.

This paper aims to present the results of a numerical investigation of the fluid dynamics and heat transfer behavior of forced incompressible flow inside a rectangular wavy channel. Reynolds numbers, based on hydraulic inlet diameter and bulk velocity, ranging from 500 to 10000 are investigated.

The numerical analysis is performed by means of a finite volume commercial CFD code. A Reynolds Averaged Navier‐Stokes (RANS) approach is applied to a three‐dimensional fluid domain over a single module with periodic conditions. Further analysis over six modules is also performed to validate the periodic numerical domain.

Mean velocity and temperature fields are obtained. The global values of Nusselt number are compared with data obtained by an experimental facility with the same geometry and operating with Re from 1000 to 10000.

Some limitations related to the numerical approach used are observed in laminar‐turbulent transitional regime at Reynolds number between 1000 and 2000 and in the transient prediction. More expensive numerical method might be used (LES approach) to improve transitional prediction.

The numerical model can be used to understand flow and thermal fields on the present configuration. A major knowledge of fluid dynamics and heat transfer processes may support the design and optimization of heat exchangers.

The validation of numerical model permits supporting experimental campaigns. A faster and cheaper optimization process for improving the performance of the component is thus made available for designers, product engineers and R&D researchers.

The purpose of this paper is to develop new semi-empirical heat transfer correlations for turbulent flow of liquid metals in the tubes, and then to compare these correlations with the experimental data. The Prandtl and Reynolds numbers can vary in the ranges: 0.0001 ≤ Pr ≤ 0.1 and 3000 ≤ Re ≤ 10⁶.

The energy conservation equation averaged by Reynolds was integrated using the universal velocity profile determined experimentally by Reichardt for the turbulent tube flow and four different models for the turbulent Prandtl number. Turbulent heat transfer in the circular tube was analyzed for a constant heat flux at the inner surface. Some constants in different models for the turbulent Prandtl number were adjusted to obtain good agreement between calculated and experimentally obtained Nusselt numbers. Subsequently, new correlations for the Nusselt number as a function of a Peclet number was proposed for different models of the turbulent Prandtl number.

The inclusion of turbulent Prandtl number greater than one and the experimentally determined velocity profile of the fluid in the tube while solving the energy conservation equation improved the compatibility of calculated Nusselt numbers, with Nusselt numbers determined experimentally. The correlations proposed in the paper have a sound theoretical basis and give Nusselt number values that are in good agreement with the experimental data.

Heat transfer correlations proposed in this paper were derived assuming a constant heat flux at the inner surface of the tube. However, they can also be used for a constant wall temperature, as for the turbulent flow (Re > 3,000), the relative difference between the Nusselt number for uniform wall heat flux and uniform wall temperature is very low.

Unified, systematic approach to derive correlations for the Nusselt number for liquid metals was proposed in the paper. The Nusselt number was obtained from the solution of the energy conservation equation using the universal velocity profile and eddy diffusivity determined experimentally, and various models for the turbulent Prandtl number. Four different relationships for the Nusselt number proposed in the paper were compared with the experimental data.