Triple Concentric Tube Heat Exchanger Research Articles

Characterization of a triple concentric-tube heat exchanger with corrugated tubes using Artificial Neural Networks (ANN)

This work presents a model of Artificial Neural Networks (ANNs) capable of accurately predicting the heat transfer rate and pressure drop in a triple concentric-tube heat exchanger (TTHX) with corrugated and non-corrugated inner tubes and involving a fluid typically used in the food industry. Pitch and depth are varied in the case of corrugated tubes. The ANN model was developed and validated using a huge databank including 181 experimental datasets. The best training algorithm is the Bayesian regulation. A back-propagation algorithm, which is considered to be the most common learning method for ANNs, is used in the training and testing of the network. Different network configurations were tested, and the optimum ANN configuration consisted of a network with two hidden layers with 15 and 21 nodes in the first and second layer, respectively. The ANNs results were found to be in good agreement with the experimental data, with the absolute average relative deviation (AARD) being below 1.91% for the heat transfer coefficient and below 3.82% for the pressure drop, respectively. The simplicity of the developed ANN model and its low levels of error for a huge experimental databank are some of the key features of the model.

Investigation of thermohydraulic performance of triple concentric‐tube heat exchanger with CuO/water nanofluid: Numerical approach

AbstractIn this study, numerical investigation of CuO/water nanofluids in a triple concentric‐tube heat exchanger has been carried out using a commercial CFD software. The primary objective of this study is to conduct a heat transfer and pressure drop characteristics of water‐based CuO nanofluids under turbulent flow regime. Reynolds number for the nanofluid has also been considered in the range of 2500 to 10,000 with a nanoparticle volume concentration of 0% to 3%. The effects of flow rate, volume concentration of nanoparticles, and flow arrangement on heat transfer performance of nanofluid have been studied for four flow arrangements. The comparison of the performance with and without nanofluid has been done. It was found that thermal performance and overall effectiveness increased with the increase in Reynolds number and volume concentration of nanoparticles in all the four flow arrangements for the considered range of operating parameters.

Thermohydraulic optimization of triple concentric-tube heat exchanger: A multi-objective approach

In the present study, optimization of heat transfer and pressure drop characteristics in a triple concentric tube heat exchanger has been done using the results of numerical simulation. A commercial CFD software ANSYS Fluent v17.0 has been employed for simulating the flow and heat transfer, while optimization has been done by Response surface methodology (RSM) and Genetic algorithm (GA). The effective parameters in the study are Reynolds number (2500 ≤ Re ≤ 10,000) and Length to hydraulic diameter ratio (100 ≤ L/Dh ≤ 220). The optimum values, as well as the functional relationship between the design factors (Re and L/Dh) and response variables (Nu and f), have also been developed. It has been found that both the design factors (Re and L/Dh) have a strong influence on the response variables (Nu and f). With the increase in Re (flow rate), a large growth in Nusselt number and decline in friction factor has been observed. However, with the increase in L/Dh, an enormous decrease in both Nusselt number and friction factor has been found.

Optimal diameters of triple concentric-tube heat exchangers

Optimal diameters of triple concentric-tube heat exchangers

Comparative Study on Concentric Triple Tube Heat Exchangers Using (GA)

We developed a computer program using the (NTU) method to determine the temperature profiles of the three fluids flowing in the heat exchanger, the minimum power consumed and the different costs in a counter-current triple concentric-tube heat exchanger in a steady state. A Genetic Algorithm (GA) is used to optimize the triple concentric-tube heat exchangers by determining the optimal diameter. Now we have only one optimum diameter which corresponds to the minimum total cost, unlike previous studies, where we had two optimal diameters, the first diameter corresponds to the maximum efficiency and the second diameter corresponds to the minimal energy consumption required to overcome the pressure drop.

Enhancement of cooling characteristics and optimization of a triple concentric-tube heat exchanger with inserted ribs

Experimental and numerical investigation of the triple concentric-tube heat exchanger with inserted ribs has been carried out. The purpose is to evaluate the performance characteristics of the triple tube heat exchanger with rib inserts. The investigation key design parameters involve water mass flow rate, flow pattern, temperature variation, rib height and rib pitch. Numerical CFD modeling is developed using FLUENT commercial code and validation criteria is done to extend the study parameters with extra ranges. The results revealed that, the insertion of ribs to the inner annulus fluid flow of the triple tube heat exchanger participate a significant enhancement of the convective heat transfer. Higher performance index is obtained at higher rib pitch and lower rib height. A set of empirical expressions with the dimensionless design parameters have been predicted based on the obtained data.

Analysis of the heat transfer in double and triple concentric tube heat exchangers

The tubular heat exchangers (shell and tube heat exchangers and concentric tube heat exchangers) represent an important category of equipment in the petroleum refineries and are used for heating, pre-heating, cooling, condensation and evaporation purposes. The paper presents results of analysis of the heat transfer to cool a petroleum product in two types of concentric tube heat exchangers: double and triple concentric tube heat exchangers. The cooling agent is water. The triple concentric tube heat exchanger is a modified constructive version of double concentric tube heat exchanger by adding an intermediate tube. This intermediate tube improves the heat transfer by increasing the heat area per unit length. The analysis of the heat transfer is made using experimental data obtained during the tests in a double and triple concentric tube heat exchanger. The flow rates of fluids, inlet and outlet temperatures of water and petroleum product are used in determining the performance of both heat exchangers. Principally, for both apparatus are calculated the overall heat transfer coefficients and the heat exchange surfaces. The presented results shows that triple concentric tube heat exchangers provide better heat transfer efficiencies compared to the double concentric tube heat exchangers.

Steady and unsteady state thermal behaviour of triple concentric-tube heat exchanger

This paper presents a numerical analysis by using the finite difference method to describe the steady and unsteady state thermal behavior of triple concentric-tube heat exchanger with parallel flow and counter flow arrangements. One gives the temperature variations of the three fluids and three walls with time along the triple concentric-tube heat exchanger. The fluids have a time lag and the response of triple concentric-tube heat exchanger in parallel flow configuration is faster than those of a counterflow arrangement, its performances are always lower than those of a counterflow triple concentric-tube heat exchanger. The heat transfer coefficients by convection of the three fluids vary with time in addition to the temperature and the heat exchanger performances are lower in unsteady state than the steady state case.

Experimental and numerical investigations of a triple concentric-tube heat exchanger

The experimental and numerical investigations of the triple concentric-tube heat exchanger are presented with particular reference to double tube heat exchanger. The purpose is to present a clear view on the thermo-fluid characteristics of this type of heat exchangers with different key design parameters leading to design optimization. Three fluids being considered are chilled water in inner tube, hot water in inner annulus, and normal tap water in outer annulus. Numerical CFD model is developed using a finite volume discretization method. The numerical model is validated and then extended to cover more extra design parameters. Four flow patterns are conducted of counter current, co-current, counter current with co-current and co-current with counter current flow. Correlations of Nusselt number, friction factor and heat exchanger effectiveness with the dimensionless design parameters are also presented. The triple tube heat exchanger contributes higher heat exchanger effectiveness and more energy saving compared with double tube heat exchanger per unit length.

Numerical Analysis of Triple Concentric Tube Heat Exchanger using Dimpled Tube Geometry

Computational Fluid Dynamic (CFD) is a useful tool in solving and analyzing problems that involve fluid flows, while triple tube concentric tube heat exchanger is the most common type of heat exchanger and widely use in chemical and food processes. In this current research to studying the Numerical Analysis of Triple Concentric Tube Heat Exchanger Using spherical shape of the Dimpled Tube Geometry, it's to create modeling and meshing the Plain and spherical dimpled geometry of triple tube concentric tube heat exchanger using the CFD package Gambit 2.4 and the boundary condition to be set before been simulate in Fluent 6.2 based on the parameters. The Hot water is flowing through in an Intermediate tube and Cold water is flowing through in an inner tube and outer tube at different Reynolds numbers. Triple Concentric tube heat exchanger performance is compared with plain and spherical shape dimpled triple concentric tube heat exchanger using CFD. From this result the simulation of in triple concentric tube heat exchanger enhancing spherical dimpled tube model to increasing the overall heat transfer coefficient, effectiveness and heat transfer rate compare to plain tube, and also calculate the flow characteristics of velocity, Nusselt number, pressure drop and Friction factor of the triple concentric tube heat exchanger spherical dimpled tube.

Prediction of the outlet temperatures in triple concentric—tube heat exchangers in laminar flow regime: case study

In this study there has been developed a numerical model of predicting outlet temperatures in a triple concentric-tube heat exchanger. For the model elaboration there have been used the equations of heat transfer and of fluid-dynamics, as well as a numerical algorithm to solve systems of non-linear equations. Based on experimental data, the obtained model has been practically tested to cool a petroleum product with water in a triple concentric-tube heat exchanger. The results obtained using the numerical simulation have been compared with the experimental data and data from literature in order to validate the proposed numerical model.

Experimental investigations on thermo-hydraulic behaviour of triple concentric-tube heat exchanger

The thermo-hydraulic investigations for triple concentric-tube heat exchanger with two-thermal communications have been experimentally carried out at steady state conditions. Water at different temperature was passed through the inner tube, the inner annulus and through the outer annulus. Experiments were performed at all possible flow arrangements for Reynolds number ranging from 2800 to 11,000 of hot water in inner annulus. Validations of experimental results have also been carried out with the established results. Experimental investigations have been carried out to measure the variations in temperature of fluid streams along the length of heat exchanger and variations of friction factor and of Nusselt number with Reynolds number.

Ventilation Heat Recovery from Wood-Burning Domestic Flues. A Theoretical Analysis Based on a Triple Concentric Tube Heat Exchanger

This paper presents a new air-heating system concept for energy-efficient dwellings. It is a system designed to heat a low-energy building by coupling a heat-recovery ventilation system with a three-fluid heat exchanger located on the chimney of a wood-pellet stove. The proposed work focuses on the heat transfer that occurs between flue gases, the ventilation air and the combustion air within a triple concentric tube heat exchanger with no insulation at its outer surface. The main objective is to predict outlet temperature for the specific geometry of the heat exchanger studied here. Thus, the governing differential equations are derived for a counter-co-current flow arrangement of the three fluids. Then analytical solutions for the steady-state temperature distribution are obtained as well as the amount of heat transferred to the outside. An expression for the effectiveness of the heat exchanger is also proposed. Based on these results, calculations are performed on a case study to predict the fluid temperature distribution along the heat exchanger. Finally, a parametric study is carried out on this case study to assess the influence of the relevant parameters on the effectiveness of the heat exchanger. In addition, computation of heat losses to the outside justifies whether insulation is needed.

Experimental Study of a Triple Concentric Tube Heat Exchanger Integrated into a Wood-Based Air-Heating System for Energy-Efficient Dwellings

In this paper, experimental tests conducted on a new wood-based air-heating system for energy-efficient dwellings are presented. The main objective is to evaluate the resulting outlet temperatures and the amount of heat recovered by the ventilation air in order to assess feasibility and performance of coupling a mechanical ventilation heat-recovery unit and a triple concentric tube heat exchanger integrated into the chimney of a room-sealed wood-pellet stove to heat an entire house. After introducing the context of this work, the three main components of the combined system developed here, the coupling configuration adopted, as well as the protocol used and the sensors implemented on an experimental setup carried out in a laboratory are detailed in turn. Then, the heat transfer rates obtained from measurements for the various fluids as well as the effectiveness of the heat exchangers are presented and discussed. Finally, the resulting outlet temperatures of the three fluids exchanging in the triple concentric tube heat exchanger studied here are compared to those provided by analytical solutions obtained with a mathematical model. It is shown that heat transfer rates are predicted with a relative difference that is lower than 5% compared to experimental values and that such a system enables to cover all or most of heat losses in an energy efficient building.

Procedure for CFD Analysis of a Triple Concentric Tube Heat Exchanger using ANSYS

Present study will be about the procedure of CFD analysis of a triple concentric heat exchanger. Computational Fluid Dynamics is a growing phenomena in the field of design and heat transfer studies. CFD software, ANSYS Workbench is a one used in a phenomenal way throughout various industries that have their work in heat transfer processes. Here, the specific focus will be on the analysis of the fluid flow and heat transfer in a Triple Concentric Tube Heat Exchanger (TCTHE) which has three different fluids, fluid 1 running through the innermost tube, fluid 2 running through the intermediate tube (i.e. inner annulus) and fluid 3 running through the outermost tube (i.e. outer annulus).

Design Development and Heat Transfer Analysis of a Triple Concentric Tube Heat Exchanger

Design Development and Heat Transfer Analysis of a Triple Concentric Tube Heat Exchanger

CFD Analysis of a Triple Concentric Tube Heat Exchanger having water flowing at three different temperatures

CFD Analysis of a Triple Concentric Tube Heat Exchanger having water flowing at three different temperatures

05/01318 Numerical simulation of triple concentric-tube heat exchangers

05/01318 Numerical simulation of triple concentric-tube heat exchangers

Numerical simulation of triple concentric-tube heat exchangers

A detailed one-dimensional steady and transient numerical simulation of the thermal and fluid-dynamic behaviour of triple concentric-tube heat exchangers has been developed. The governing equations (continuity, momentum and energy) inside the inner tube and the annulus (inner and outer), together with the energy equations in the inner, intermediate and outermost tube wall and insulation, are solved iteratively in a segregated manner. The discretized governing equations in the zones with fluid flow are coupled using an implicit step by step method. This formulation requires the use of empirical information for the evaluation of convective heat transfer, shear stress and void fraction. An implicit central difference numerical scheme and a line-by-line solver was used in the inner and intermediate tube walls and the outermost tube wall with insulation. All the flow variables (enthalpies, temperatures, pressures, mass fractions, velocities, heat fluxes, etc.) together with the thermophysical properties are evaluated at each point of the grid in which the domain is discretized. Different numerical aspects and comparisons with results obtained from the technical literature are presented in order to verify and validate the model.

EFFECTIVENESS-NTU RELATIONS FOR TRIPLE CONCENTRIC-TUBE HEAT EXCHANGES

T In this study, closed form expressions for the effectiveness- NTU relations are derived for triple concentric-tube heat exchangers including both counter-flow and parallel-flow arrangements. In addition, some representative data for both types of flow arrangements are presented in graphical form.