Showing papers on "Concentric tube heat exchanger published in 2015"
TL;DR: In this article, the effect of longitudinal fins in a double-pipe heat exchanger containing PCM is examined during charging process, where eight rectangular fins are mounted around the HTF (heat transfer fluid) carrying tube.
159 citations
TL;DR: In this paper, a double-pipe heat exchanger made of corrugated outer and inner tubes was investigated, where both of the inner and outer tubes were made by means of a special machine and the heat transfer coefficient was determined using Wilson plots.
126 citations
TL;DR: In this paper, the forced convective heat transfer coefficient of a biologically produced nanofluid flowing in a circular tube inside a heat exchanger was investigated and a new correlation was proposed with absolute average deviation of 3.43.
117 citations
TL;DR: In this paper, the authors presented an experimental investigation on enhanced heat transfer and pressure loss characteristics by using single, double, triple, and quadruple twisted-tape inserts in a round tube having a uniform heat-fluxed wall.
84 citations
TL;DR: In this paper, the forced convective heat transfer due to flow of Al2O3/Water nanofluid through a circular tube filled with a metal foam is investigated experimentally.
80 citations
TL;DR: In this paper, the topology of pin-fins (length, diameter, and shape) is optimized based on the entropy generation minimization (EGM) theory coupled with the constructal law (CL).
Abstract: Pin-fins are considered as one of the best elements for heat transfer enhancement in heat exchangers. In this study, the topology of pin-fins (length, diameter, and shape) is optimized based on the entropy generation minimization (EGM) theory coupled with the constructal law (CL). Such pin-fins are employed in a heat exchanger in a sensible thermal energy storage (TES) system so as to enhance the rate of heat transfer. First, the EGM method is used to obtain the optimal length of pin-fins, and then the CL is applied to get the optimal diameter and shape of pin-fins. Reliable computational fluid dynamics (CFD) simulations of various constructal pin-fin models are performed, and detailed flow and heat transfer characteristics are presented. The results show that by using the proposed system with optimized pin-fin heat exchanger the stored thermal energy can be increased by 10.2%.
78 citations
TL;DR: In this paper, the authors compared the effect of buoyancy on heat transfer to supercritical water in an internally ribbed tube and a smooth tube, and found that buoyancy had a weaker impact on the heat transfer than smooth tubes.
76 citations
TL;DR: In this paper, the authors provided an overview of the published works that are relevant to the tube banks heat exchangers and showed that the heat transfer and pressure drop characteristics of the heat exchanger rely on many parameters such as external fluid velocity, tube configuration, tube rows, tube spacing, fin spacing, shape of tubes, etc.
Abstract: The heat exchangers have a widespread use in industrial, transportation as well as domestic applications such as thermal power plants, means of transport, air conditioning and heating systems, electronic equipment and space vehicles. The key objectives of this article are to provide an overview of the published works that are relevant to the tube banks heat exchangers. A review of available and display that the heat transfer and pressure drop characteristics of the heat exchanger rely on many parameters. Such parameters as follows: external fluid velocity, tube configuration (in-line/staggered, series), tubes rows, tube spacing, fin spacing, shape of tubes, etc. The review also shows the finned and un-finned tube configurations heat exchangers. The important correlations for thermofluids in tube banks heat exchangers also discussed. The optimum spacing of tube-to-tube and fin-to-fin with fixed size (i.e., area, volume) with the maximum overall heat conductance (heat transfer rate) were summarized in this review. In addition, the few studies show the effect of tube diameter in a circular shape compared with elliptic tube shape. Overall, the heat transfer coefficient and pressure drop increases with increasing fluid velocity regardless the arrangement and shape of the tube. In the meantime, the other shape of tubes (such as flat or flattened) for finned and un-finned with the optimum design needs more research and investigation due to have lesser air-side pressure drop and improved air-side heat transfer coefficients. They have putted some the significant conclusions from this review.
74 citations
TL;DR: In this paper, the renormalization group RNG k-e model was used to simulate the three-dimensional turbulent heat transfer of CO2 in a helical pipe at near-critical pressure.
74 citations
TL;DR: In this paper, a Transport Membrane Condenser (TMC) made from nanoporous membrane tube bundles was developed to recover the water vapor and its significant amount of latent heat from boiler flue gases to improve boiler efficiency and save water.
72 citations
TL;DR: In this paper, a U-bend heat exchanger with and without helical tape inserts in the inner tube was studied experimentally, and the experiments were conducted in the Reynolds number range from 3000 to 30,000, volume concentrations of 0.01%, 0.03% and helical Tape inserts of p/d = 5, 10, 15 and 20.
TL;DR: In this article, the Nusselt number and friction factor of water flow inside a plate heat exchanger with a rough surface are predicted. But the authors did not consider the impact of surface roughness on the heat transfer coefficient.
TL;DR: In this paper, a two-dimensional numerical CFD model using finite volume discretization is used to evaluate the performance of different tube bundles arrangements, and the effects of pressure drop, exergy and enthalpy balances are both investigated.
TL;DR: In this paper, a comparative evaluation of alternative compact heat exchanger designs for use as the intermediate heat exchangers in advanced nuclear reactor systems is presented, and the wavy channel PCHE with a 15° pitch angle was found to offer optimum combination of heat transfer coefficient, compactness and pressure drop as compared to other alternatives.
TL;DR: In this paper, a new fin pattern with curved delta-winglet vortex generators (CDWVGs) punched on fin surface was proposed to reduce the peeling wake area and generate longitudinal vortices at the rear of circular tube employed in tube bank fin heat exchanger.
TL;DR: In this paper, an attempt was made to increase the number of thermal units (NTU) and performance in a vertical shell and coiled tube heat exchanger via air bubble injection into the shell side.
TL;DR: In this article, a 3D numerical investigation has been carried out to examine periodic laminar flow and heat transfer characteristics in a circular tube with 45° V-baffles with isothermal wall.
TL;DR: In this article, the heat transfer and friction characteristics of a concentric tube heat exchanger with different pitches of coiled wire turbulators were investigated experimentally and numerically, and the results were correlated in the form of Nusselt number as a function of Reynolds number and Prandtl number.
TL;DR: In this article, a finite volume method and integral averaging of gas temperature across a tube row is proposed for modeling of plate fin and tube heat exchangers, especially for exchangers in which substantial gas temperature differences in one tube row occur.
TL;DR: The tube-in-tube heat exchanger is comprised of two concentric alumina tubes, each filled with reticulated porous alumina with a nominal porosity of 80% and pore density of 5 pi.
TL;DR: In this paper, a novel shell-and-tube heat exchanger with new plate baffles is proposed, which is numerically investigated in comparison with a shell and tube heat exchange with rod baffles.
TL;DR: In this article, the authors investigated the turbulent convection heat transfer of supercritical pressure CO2 in a serpentine vertical mini tube with an inner diameter of 0.953mm and curvature diameter of 8.01mm.
TL;DR: In this article, the influence of the changes in geometrical factors, including the space bar thickness, the tube pitch in the first layer and the tube external diameter, on flow and heat transfer performances in multi-stream spiral-wound heat exchangers are numerical investigated.
TL;DR: In this paper, an experimental system of parabolic trough solar collector and heat transfer was set up with a new molten salt employed as the heat transfer medium (with a melting point of 86 °C and a working temperature upper limit of 550 °C).
TL;DR: In this article, the authors focused on Computational Fluid Dynamics (CFD) analysis of falling film evaporation of seawater on a single tube and bundle of tubes using ANSYS Fluent 13.0®.
TL;DR: In this paper, a new equation set describing transient heat transfer process in tube and fin cross-flow heat tube exchanger was given and subsequently solved using the finite volume method and a numerical model of a single-row heat exchanger and double-row car radiator with two passes has been developed.
TL;DR: In this article, heat transfer of a fluid containing nano water aluminum oxide with a diameter of about 20nm in a horizontal double pipe counter flow heat exchanger under turbulent flow conditions was studied.
Abstract: In this work, heat transfer of a fluid containing nanoparticles of aluminum oxide with the water volume fraction (0.1–0.3) percent has been reported. Heat transfer of the fluid containing nano water aluminum oxide with a diameter of about 20 nm in a horizontal double pipe counter flow heat exchanger under turbulent flow conditions was studied. The results showed that the heat transfer of nanofluid in comparison with the heat transfer of fluid is slightly higher than 12 percent.
TL;DR: In this paper, the authors present numerical analysis of a flow around a bundle of externally finned elliptical tubes, used in cross-flow heat exchangers of a flue-gas/water type, arranged serially in two rows.
TL;DR: In this article, an experimental and analytical investigation was conducted on an air-to-water heat exchanger equipped with six wickless heat pipes (thermosyphons) charged with water as the working fluid.
TL;DR: In this paper, multiwalled carbon nanotubes (MWCNT) were added to water to enhance heat transfer capability of water as a hot stream in plate heat exchanger.
Abstract: Increasing efficacy of plate heat exchanger (PHE) is a method of reducing energy consumption of milk pasteurization and sterilization in dairy industries. In order to enhance heat transfer capability of water as a hot stream in PHEs, multiwalled carbon nanotubes (MWCNT) were added to water. An experimental setup was designed and manufactured to measure heat transfer coefficient and Nusselt number (Nu) as two key parameters for convective heat transfer. This system had two individual loops for hot and cold fluids. The experimental results clearly indicated that heat transfer coefficient and Nu number of pure water increased by adding MWCNT with weight concentration of less than 1 wt%. With increasing weight concentration of the nanoparticles, heat transfer coefficient and Nu number increased. This augmentation was intensified at higher Peclet numbers which showed more effective presence of them at high flow rates of nanofluids. Moreover, at constant weight concentration, both heat transfer coefficient and ...