Showing papers on "Concentric tube heat exchanger published in 2017"
TL;DR: In this article, the sensitivity analysis of heat transfer and heat exchanger effectiveness in a double pipe heat exchange with Al 2 O 3 nanofluid was investigated using the Response Surface Methodology (RSM) and two phase mixture model.
162 citations
TL;DR: In this article, the effect of using water/graphene oxide nanofluid as a working fluid on heat transfer and pressure drop was studied experimentally in a tube under air cross-flow.
101 citations
TL;DR: In order to further improve the heat transfer performance of compact heat exchanger, curved delta winglet vortex generators with different geometric sizes are experimentally studied for circular tube-and-fin this paper.
97 citations
TL;DR: In this article, a numerical model of shell and helical tube heat exchanger is investigated to assess heat transfer coefficient and exergy loss, and four design parameters including pitch coil, tube diameter, hot and cold flow rate, which are more significant for the heat exchange performance, were taken to consideration.
90 citations
TL;DR: In this article, the effect of using Al2O3-water nanofluid on thermal performance of a commercial shell and tube heat exchanger with segmental baffles is assessed experimentally.
86 citations
TL;DR: In this article, the volume concentrations of the nanoparticles used in this study are 0.005, 0.01, 1.03, and 0.06% with Reynolds number range from 15,000 to 30,000.
86 citations
TL;DR: In this article, the phase-change material melting in a triplex tube heat exchanger has been investigated numerically in a two-dimensional numerical model using fluent software and conduction and natural convection are taken into account in this simulation.
86 citations
TL;DR: In this article, the design and thermo-hydraulic performance of a double-pipe heat exchanger with helical baffles in the annulus side, are investigated numerically.
84 citations
TL;DR: In this article, the authors studied thermal-hydraulic performance characteristics in a tube bank compact heat exchanger with introducing new design of fins and tube by using computational fluid dynamics approach.
79 citations
TL;DR: In this paper, the effects of Al2O3/water nanofluid on the hydrodynamics and convective heat transfer of a counter flow double-tube heat exchanger were investigated.
Abstract: Double-tube heat exchanger is primarily adapted to high-temperature, high-pressure applications due to their relatively small diameters. An experimental study performed to investigate the effects of Al2O3/water nanofluid on the hydrodynamics and convective heat transfer of a counter flow double-tube heat exchanger. The nanofluid was used as hot fluid and passed through the inner tube of the heat exchanger considering fully developed turbulent flow regime. Experiments were conducted at the nanofluid flow rates of 7, 9, and 11 L min−1, nanofluid inlet temperatures of 45, 55, and 65 °C, and dilute nanoparticle concentrations of 0.05 and 0.15 vol%. Local convective heat transfer coefficient in double-tube heat exchanger has been measured experimentally for the first time. Results showed that nanofluids had higher Nusselt number than pure water. Also, the Nusselt number increased by increasing particles volume fraction, flow rate as well as temperature of nanofluid. However, increasing the convective heat transfer coefficient of the nanofluids was not sensible with increasing the concentration. In addition, the ratio of the heat transfer coefficient of nanofluid to that of the base fluid decreased by increasing Reynolds number. Adding γ-Al2O3 nanoparticles to the base fluid increased the friction factor. In this study, the greatest enhancement in the heat transfer coefficient and the friction factor obtained at 0.15 vol% concentration of nanoparticles which were 23 and 25 %, respectively.
77 citations
TL;DR: In this paper, the effects of different lengths of twisted tapes on heat transfer enhancement were studied through a circular tube using water as testing fluid in turbulent conditions with a range of Reynolds number between 3000 and 9000.
TL;DR: In this paper, the authors compared the flow and heat transfer characteristics of TiO2-water nanofluids and deionized water in test tubes, and the effects of Reynolds number (Re) and nanoparticle mass fraction (ω) on flow performance were discussed.
TL;DR: In this paper, an Artificial Neural Network (ANN) model is developed to predict the convective heat transfer coefficients in both wall, and the pressure drop in terms of radius ratio, volume concentration, and particle size.
TL;DR: In this article, the thermal hydraulic performance of fin tube heat exchangers with circular, oval and flat tubes having inline and staggered arrangement was evaluated and the MOORA (multiobjective optimization on the basis of ratio analysis) method was employed to obtain the order of performance and that order is compared with the conventional PECs (performance evaluation criteria), showing good agreements.
TL;DR: In this paper, the authors investigated the heat transfer and pressure drop of R-134a during condensation inside a dimpled tube and found that the dimpled tubes obtained higher heat transfer coefficient and frictional pressure drop than the smooth tubes.
TL;DR: In this paper, the authors have achieved the maximum heat transfer coefficient and Nusselt number with helical shaped ribs of 4mm pitch and 1.5mm depth with the variations in Reynolds number from 5000 to 17,000.
TL;DR: In this paper, a helical wire has been placed inside the helically coiled tube as a turbulator to increase the thermal and frictional characteristics of heat exchanger, which significantly increased the overall heat transfer coefficient and obviously pressure drop.
TL;DR: In this paper, numerical simulations were performed for the fouling characteristics and heat transfer performance after fouling on the H-type finned tube heat exchangers, and the optimum parameters studies were also conducted according to the orthogonal array design method.
TL;DR: In this article, the heat transfer intensification in shell and helically coiled tube heat exchangers via installing annular fins on the outer surface of the helical coil, has been numerically investigated.
Abstract: In this work, the heat transfer intensification in shell and helically coiled tube heat exchangers via installing annular fins on the outer surface of the helical coil, has been numerically investigated. Thirteen heat exchangers were designed for this purpose. All geometrical parameters of the heat exchangers are same except, fin's number or height. All of the heat exchangers have been studied at three different shell side Reynolds number (Re sh = 7500, 15,000 and 30,000). In order to validation of the numerical model two method has been used. In the first method, the calculated heat transfer has been compared with the approximate method which is based on the experimental correlations for both coil and shell side Nusselt numbers and consideration of the E-NTU relations of these types of heat exchangers. In the second method, the heat transfer coefficient of the shell side has been compared with the experimental heat transfer coefficients of the previous works. An acceptable agreement has been observed in these comparisons. Furthermore, the optimum cases and some correlations have been obtained for prediction of the heat transfer coefficient of the shell side. Results indicate that, in the range of 7500 ≤ Re sh ≤ 30,000, the heat transfer rate can increase up to 44.11%.
TL;DR: In this paper, the performance of an absorber tube with heat transfer enhancer in solar flat plate water heater was investigated, and it was found that the rod heat-transfer enhancer provided higher heat transfer with a small increase in pumping power than tube heat transfer enhancement and plain tube flat plate solar collector.
TL;DR: In this paper, the authors investigated the heat transfer behavior of a tube with twisted tape swirl generator for different values of the twist ratio and diameter ratio and for Reynolds numbers within the range 100-20,000.
Abstract: Heat transfer behaviour in a tube with inserted twisted tape swirl generator is investigated numerically, for different values of the twist ratio and diameter ratio and for Reynolds numbers within the range 100-20,000. The transition-SST model is used as the turbulence model. The computational model is validated, first, on a plain tube, where a good agreement is achieved with the correlations. The subsequent analysis of the tube with twisted tape indicates that the use of twist tape enhances heat transfer generally, which is accompanied by a higher pressure drop. It is observed that an improvement of the thermal-hydraulic performance can only be observed for certain configurations and Reynolds numbers.
TL;DR: In this paper, the effects of configuration parameters of spiral-wound heat exchanger (SWHE) on flow and heat transfer characteristics were numerically studied based on the method combining Genetic Aggregation response surface and Multi-Objective Genetic Algorithm.
TL;DR: In this paper, a new procedure for injecting the air bubbles into the shell side flow of the heat exchanger is proposed, and the results exhibited a significant increase in the effectiveness and number of thermal units (NTU), exergy loss and effectiveness due to air bubbles injection with different air flow rates.
TL;DR: In this article, the single-phase heat transfer for nine brazed-plate heat exchangers with different geometric parameters is experimentally investigated, and the results show that the herringbone angle is the most dominant factor influencing heat transfer.
TL;DR: In this article, the authors investigated the heat transfer characteristics of a condenser tube in a passive containment cooling system (PCCS) of an advanced nuclear power plant, and found that the condensation heat transfer coefficients on a vertical tube were significantly influenced by the strength of natural convection of the air-steam mixture, which can be described by the Grashof number.
TL;DR: In this paper, twisted tape inserts are used to enhance convection heat transfer with an accompanying rise in pressure drop where the enhancement is essentially attributed to the secondary swirl flow, which increases the friction factor by ten fold and the Nusselt number by three folds.
TL;DR: In this paper, the design and analysis of a shell and tube heat exchanger used to combine parabolic trough solar collectors (PTSCs) and an organic Rankine cycle (ORC) based geothermal power plant is presented.
TL;DR: In this article, the authors investigated the air-side thermal-hydraulic characteristics of the plain tube bank and plain finned tube heat exchangers intended for use in aero-engine cooling.
TL;DR: In this paper, the Darcy-Brinkman-Forchheimer model is applied to model the flow field in the porous zone. And the sensitivity analysis is performed utilizing the Response Surface Methodology.
TL;DR: In this paper, a fin-and-tube heat exchanger with rectangular winglet pairs has been numerically investigated by solving the conservation equations of mass, momentum and energy, where the flow is assumed to be laminar at different Reynolds numbers.