Thermal Performance Evaluation of a Double Pipe Heat Exchanger Installed in a Biomass Gasification System

Heat exchangers are widely used for heat recovery purposes in many industrial applications such as gasification systems. In a biomass gasification system situated at Melani village in Eastern Cape of South Africa, a significant quantity of heat energy is lost during syngas cooling. Thus, a heat exchanger was constructed and installed in the gasification system for the purpose of heat recovery. Therefore, the aim of this study is to evaluate the performance of the heat exchanger under variable operating conditions for counterflow and parallel flow configurations. The experimental investigation was carried out on a double pipe heat exchanger as the downdraft gasifier system operated on a wood consumption rate of 180 kg/h. The heat exchanger was installed at the exit point of the syngas in the gasifier, and water served as the cooling fluid. Inlet and outlet temperatures of the hot syngas and cooling water (fluids) were measured using thermocouples at variable flow rates. Experimental data were processed using energy equations to determine vital performance parameters (overall heat transfer coefficient, effectiveness, and log mean temperature difference). The findings showed that optimum heat exchanger effectiveness of 0.55 was determined at a mass flow rate of 0.07 kg/s. In addition, counterflow configuration was found to be approximately 14% more effective than the parallel flow configuration. This is attributed to the relative direction of the fluids in the configurations of both flows. The study recommends that double pipe heat exchanger is suitable for recovering heat from the gasification system.

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Derive The NTU-Effectiveness Formula For The Double Pipe Heat Exchanger In Parallel Flow Arrangement

10.37376/1571-000-044-005 ◽

2017 ◽

pp. 1

Author(s):

Elmuataz Moftah ◽

Ahmad Abdelaly ◽

Ali Gebriel ◽

Wahbe Pohwess

Keyword(s):

Heat Exchanger ◽

Parallel Flow ◽

Double Pipe ◽

Pipe Heat

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Thermal–Hydraulic Performance Analysis of a Convergent Double Pipe Heat Exchanger

Journal of Heat Transfer ◽

10.1115/1.4042487 ◽

2019 ◽

Vol 141 (5) ◽

Cited By ~ 1

Author(s):

Ahmed T. Al-Sammarraie ◽

Kambiz Vafai

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Hydraulic Performance ◽

Operating Conditions ◽

Contraction Ratio ◽

Wide Range ◽

Prandtl Numbers ◽

Double Pipe ◽

The Impact ◽

Pipe Heat

The present investigation proposes an innovative convergent double pipe heat exchanger (C-DPHE). A two-dimensional (2D) axisymmetric heat transfer model with counterflow is employed to analyze the thermal and hydraulic performance of this configuration numerically. The impact of convergence in the flow direction, using a wide range of contraction ratio (Cr), is explored. The effect of Reynolds and Prandtl numbers on the flow and heat transfer is addressed, as well. The model results were validated with available data from the literature, and an excellent agreement has been confirmed. In general, the findings of the present study indicate that increasing the contraction ratio increases heat transfer and pressure drop in the C-DPHE. Moreover, this configuration has a prominent and sustainable performance, compared to a conventional double pipe heat exchanger (DPHE), with an enhancement in heat transfer rate up to 32% and performance factor (PF) higher than one. Another appealing merit for the C-DPHE is that it is quite effective and functional at low Reynolds and high Prandtl numbers, respectively, since no high-operating pumping power is required. Further, the optimal operating conditions can be established utilizing the comprehensive information provided in this work.

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Experimental and CFD Analysis of GW70 based Cu Nanofluids in a Parallel Flow Heat Exchanger

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.d6587.1110421 ◽

2021 ◽

Vol 10 (4) ◽

pp. 106-110

Author(s):

M.L.R. Chaitanya Lahari ◽

◽

P.H.V. Sesha Talpa Sai ◽

K.V. Sharma ◽

K.S. Narayanaswamy ◽

...

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Mass Flow ◽

Parallel Flow ◽

Hot Water ◽

Cfd Analysis ◽

Flow Rates ◽

Mass Flow Rates ◽

Double Pipe ◽

Pipe Heat

The Nusselt number, overall heat transfer, and convective heat transfer coefficients of glycerol-water-based Cu nanofluids flowing in a parallel flow double pipe heat exchanger are estimated using CFD analysis. Single-phase fluid approach technique is used in the analysis. Ansys 19.0 workbench was used to create the heat exchanger model. Heat transfer tests with nanofluids at three flow rates (680<Re<1900) are carried out in a laminar developing flow zone. For testing, a 500 mm long concentric double pipe heat exchanger with tube dimensions of ID=10.2 mm, OD= 12.7 mm, and annulus dimensions of ID=17.0 mm, OD= 19.5 mm is employed. Copper is utilized for the tube and annulus material. This study employed three-particle volume concentrations of 0.2 percent, 0.6 percent, and 1.0 percent. The mass flow rates of hot water in the tube are 0.2, 0.017, and 0.0085 kg/s, while the mass flow rates of nanofluids in the annulus are 0.03, 0.0255, and 0.017 kg/s. The average temperature of nanofluids is 36°C, whereas hot water is 58°C. In comparison to base liquid, the overall heat transfer coefficient and convective HTC of 1.0 percent copper nanofluids at 0.03 kg/s are raised by 26.2 and 46.2 percent, respectively. The experimental findings are compared to CFD values, and they are in close agreement.

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Tentative Study and Examination of different Tube Geometry with Helix Angle 600 Double Pipe Heat Exchanger for Parallel Flow

International Journal for Research in Applied Science and Engineering Technology ◽

10.22214/ijraset.2019.10063 ◽

2019 ◽

Vol 7 (10) ◽

pp. 408-422

Author(s):

Sanjay Kumar Koli

Keyword(s):

Heat Exchanger ◽

Helix Angle ◽

Parallel Flow ◽

Double Pipe ◽

Tube Geometry ◽

Pipe Heat

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Predicting Performance of Double-Pipe Parallel- and Counter-Flow Heat Exchanger Using Fuzzy Logic

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4044696 ◽

2019 ◽

Vol 12 (3) ◽

Cited By ~ 5

Author(s):

M. Sridharan

Keyword(s):

Experimental Data ◽

Fuzzy Logic ◽

Heat Exchanger ◽

Industrial Applications ◽

Parallel Flow ◽

Data Sets ◽

Counter Flow ◽

Two Fluids ◽

Exit Temperature ◽

Double Pipe

Abstract The heat exchanger is a device in which heat transfer takes place between two fluids at different temperatures. Among various classifications of heat exchangers, parallel and counter flow types are used widely in many industrial applications. This paper presents two fuzzy logic expert systems (FLESs), one for parallel-flow and another for counter-flow double-pipe heat exchanger (DPHE). Such FLESs are capable of predicting the exit temperature of heat carrier fluids and its effectiveness in an accurate manner. In total, 96 sets of experiments have been conducted for parallel and counter flow types under different combinations of the mass flow rate. The performance accuracy of the fuzzy logic expert system is measured by comparing fuzzy predicted results with experimental data sets. Such a comparison indicates a good agreement between experimental data sets and fuzzy predicted results. The accuracy of the parallel-flow FLES in predicting the exit temperature and its effectiveness is 92.78% and 95%, respectively. The accuracy of the counter-flow FLES in predicting the exit temperature and its effectiveness is 94.28% and 95.5%, respectively.

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A Semi Empirical Methodology for Performance Estimation of a Double Pipe Finned Heat Exchanger

Volume 4: Fatigue and Fracture; Fluids Engineering; Heat Transfer; Mechatronics; Micro and Nano Technology; Optical Engineering; Robotics; Systems Engineering; Industrial Applications ◽

10.1115/esda2008-59124 ◽

2008 ◽

Author(s):

G. Arvind Rao ◽

Yeshyahou Levy

Keyword(s):

Heat Transfer ◽

Nusselt Number ◽

Heat Exchanger ◽

Heat Exchangers ◽

Operating Conditions ◽

Performance Estimation ◽

Wide Range ◽

Double Pipe ◽

Semi Empirical ◽

Pipe Heat

Finned tubes are one of the most widely used means of passively enhancing the heat transfer in circular tubes. Many investigators have proposed different correlations for predicting the performance of such heat exchangers based on their experimental investigations. However, the practical usage of such correlations is limited because of the variety of parameters that can influence Nusselt number and friction factor. Most of the correlations either have been developed with limited databases, or are geometry specific. Using CFD for analyzing performance of such heat exchangers is very computational intensive and hence cannot practically be applied for design optimization purposes. On the other hand, empirical correlations have many limitations in terms of their applicability. The objective of the present article is to present a physically based model for evaluating heat transfer and frictional loss for an internally and / or externally finned double pipe heat exchanger that can be applied in a wide range of operating conditions of practical importance. This paper describes a simple semi-empirical-numerical methodology to evaluate heat transfer and pressure drop characteristics in a finned tube heat exchanger with internal and/or external fins. Conduction and turbulent forced convection are the prominent modes of heat transfer. In order to resolve the operational characteristics of double pipe finned heat exchangers, a numerical methodology is presented which uses well known existing correlations for flow in a smooth pipe and flow over a flat plate. The method of successive substitution is used to solve the problem numerically. The proposed methodology is applied to some simple cases and the results compare well with existing data and correlations available in the literature. It is found that the addition of fins to such double pipe heat exchangers reduce the Nusselt Number; however the corresponding heat transfer rate is enhanced owing to the increase in the overall heat transfer area.

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