Flow behavior of rapid thermal oscillation inside an asymmetric micro pulsating heat exchanger

2018 ◽  
Vol 120 ◽  
pp. 923-929 ◽  
Author(s):  
Young Bae Kim ◽  
Hyoung Woon Song ◽  
Jaeyong Sung
Keyword(s):  
Heat Exchanger ◽  
Flow Behavior ◽  
Thermal Oscillation

scholarly journals Analysis on thermal and flow behavior of triple concentric tube heat exchanger handling MWCNT-water nanofluids

2020 ◽  
Vol 24 (1 Part B) ◽  
pp. 487-494
Author(s):  
Chokkeyee Periyasamy ◽  
Hariprasath Visvanathan
Keyword(s):  
Heat Exchanger ◽  
Flow Behavior ◽  
Tube Heat Exchanger

A comprehensive survey on utilization of hybrid nanofluid in plate heat exchanger with various number of plates

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Faraz Afshari ◽  
Azim Doğuş Tuncer ◽  
Adnan Sözen ◽  
Halil Ibrahim Variyenli ◽  
Ataollah Khanlari ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Flow Behavior ◽  
Plate Heat Exchanger ◽  
Single Type ◽  
Hybrid Nanofluid ◽  
Content Type ◽  
Plate Heat ◽  
The Impact

Purpose Using suspended nanoparticles in the base fluid is known as one of the most efficient ways for heat transfer augmentation and improving the thermal efficiency of various heat exchangers. Different types of nanofluids are available and used in different applications. The main purpose of this study is to investigate the effects of using hybrid nanofluid and number of plates on the performance of plate heat exchanger. In this study, TiO2/water single nanofluid and TiO2-Al2O3/water hybrid nanofluid with 1% particle weight ratio have been used to prepare hybrid nanofluid to use in plate type heat exchangers with three various number of plates including 8, 12 and 16. Design/methodology/approach The experiments have been conducted with the aim of examining the impact of plates number and used nanofluids on heat transfer enhancement. The performance tests have been done at 40°C, 45°C, 50°C and 55°C set outlet temperatures and in five various Reynolds numbers between 1,600 and 3,800. Also, numerical simulation has been applied to verify the heat and flow behavior inside the heat exchangers. Findings The results indicated that using both nanofluids raised the thermal performance of all tested exchangers which have a various number of plates. While the major outcomes of this study showed that TiO2-Al2O3/water hybrid nanofluid has priority when compared to TiO2/water single type nanofluid. Utilization of TiO2-Al2O3/water nanofluid led to obtaining an average improvement of 7.5%, 9.6% and 12.3% in heat transfer of heat exchangers with 8, 12 and 16 plates, respectively. Originality/value In the present work, experimental and numerical analyzes have been conducted to investigate the influence of using TiO2-Al2O3/water hybrid nanofluid in various plate heat exchangers. The attained findings showed successful utilization of TiO2-Al2O3/water nanofluid. Based on the obtained results increasing the number of plates in the heat exchanger caused to obtain more increment by using both types of nanofluids.

A Numerical Study of Flow and Heat Transfer Enhancement Using an Array of Delta-Winglet Vortex Generators in a Fin-and-Tube Heat Exchanger

2006 ◽  
Vol 129 (9) ◽  
pp. 1156-1167 ◽  
Author(s):  
A. Joardar ◽  
A. M. Jacobi
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Numerical Study ◽  
Flow Behavior ◽  
Vortex Generators ◽  
Computational Domain ◽  
Transfer Enhancement ◽  
Local Flow ◽  
Tube Heat Exchanger

This work is aimed at assessing the potential of winglet-type vortex generator (VG) “arrays” for multirow inline-tube heat exchangers with an emphasis on providing fundamental understanding of the relation between local flow behavior and heat transfer enhancement mechanisms. Three different winglet configurations in common-flow-up arrangement are analyzed in the seven-row compact fin-and-tube heat exchanger: (a) single–VG pair; (b) a 3VG-inline array (alternating tube row); and (c) a 3VG-staggered array. The numerical study involves three-dimensional time-dependent modeling of unsteady laminar flow (330⩽Re⩽850) and conjugate heat transfer in the computational domain, which is set up to model the entire fin length in the air flow direction. It was found that the impingement of winglet redirected flow on the downstream tube is an important heat transfer augmentation mechanism for the common-flow-up arrangement of vortex generators in the inline-tube geometry. At Re=850 with a constant tube-wall temperature, the 3VG-inline-array configuration achieves enhancements up to 32% in total heat flux and 74% in j factor over the baseline case, with an associated pressure-drop increase of about 41%. The numerical results for the integral heat transfer quantities agree well with the available experimental measurements.

Flow and Cold Heat-Storage Characteristics of Phase-Change Emulsion in a Coiled Double-Tube Heat Exchanger

1995 ◽  
Vol 117 (2) ◽  
pp. 440-446 ◽  
Author(s):  
H. Inaba ◽  
S. Morita
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Heat Storage ◽  
Flow Behavior ◽  
Water Emulsion ◽  
Tube Heat Exchanger ◽  
The Heat Transfer Coefficient ◽  
Storage Characteristics

This paper dealt with the flow and cold heat-storage characteristics of the oil (tetradecane, C14H30, freezing point 278.9 K)/water emulsion as a latent heat-storage material having a low melting point. A coiled double-tube heat exchanger was used for the cold heat-storage experiment. The pressure drop, the heat transfer coefficient, and the finishing time of cold heat storage in the coiled tube were measured as experimental parameters. It was understood that the flow behavior of the emulsion as a non-New-tonian fluid had an important role in the present cold heat storage. The useful nondi-mensional correlation equations for the additional pressure loss coefficient, the heat transfer coefficient, and the cold heat storage time were derived in terms of modified Dean number and heat capacity ratio.

Two-Dimensional CFD Study on the Enhancement of Tube Bank Configuration Heat Exchanger

2020 ◽  
Author(s):  
Ahmed M. Nagib Elmekawy ◽  
Abdalrahman M. Shahin ◽  
Alaa A. Ibrahim ◽  
Sara Al-Ali
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Flow Behavior ◽  
Plate Thickness ◽  
Cross Flow ◽  
Splitter Plate ◽  
Thickness Variation ◽  
Two Dimensional ◽  
Tube Bank

Abstract Two-dimensional simulations are carried out for a heat exchanger to study the cross-flow behavior in a circular tube bank in a staggered configuration in case of bare cylinders and cylinders with splitter plate attachment. A considerable performance evaluation of the heat exchanger with splitter plate can be achieved by studying the heat transfer and the pressure drop of the flow. Numerical simulation results carried out from this study are compared to experimental results. The numerical investigation has been established to study the effect of splitter plate on the heat exchanger thermal performance as there were no previous studies performed on the optimization of the splitter thickness. The study also illustrates the effect of splitter plate thickness variation on pressure drop and heat transfer for different Reynolds number.

Development of Technologies on Innovative-Simplified Nuclear Power Plant Using High-Efficiency Steam Injectors: Part 12—Evaluations of Spatial Distributions of Flow and Heat Transfer in Steam Injector

2006 ◽  
Author(s):  
Yutaka Abe ◽  
Yujiro Kawamoto ◽  
Chikako Iwaki ◽  
Tadashi Narabayashi ◽  
Michitsugu Mori ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Flow Rate ◽  
Direct Contact ◽  
Nuclear Reactor ◽  
High Efficiency ◽  
Flow Behavior ◽  
Water Jet ◽  
Next Generation ◽  
Contact Condensation

Next-generation nuclear reactor systems have been under development aiming at simplified system and improvement of safety and credibility. One of the innovative technologies is the supersonic steam injector, which has been investigated as one of the most important component of the next-generation nuclear reactor. The steam injector has functions of a passive pump without large motor or turbo-machinery and a high efficiency heat exchanger. The performances of the supersonic steam injector as a pump and a heat exchanger are dependent on direct contact condensation phenomena between a supersonic steam and a sub-cooled water jet. In previous studies of the steam injector, there are studies about the operating characteristics of steam injector and about the direct contact condensation between static water pool and steam in atmosphere. However, there is a little study about the turbulent heat transfer and flow behavior under the great shear stress. In order to examine the heat transfer and flow behavior in supersonic steam injector, it is necessary to measure the spatial temperature distribution and velocity in detail. The present study, visible transparent supersonic steam injector is used to obtain the axial pressure distributions in the supersonic steam injector, as well as high speed visual observation of water jet and steam interface. The experiments are conducted with and without non-condensable gas. The experimental results of the interfacial flow behavior between steam and water jet are obtained. It is experimentally clarified that an entrainment exists on the water jet surface. It is also clarified that discharge pressure is depended on the steam supply pressure, the inlet water flow rate, the throat diameter and non-condensable flow rate. Finally a heat flux is estimated about 19MW/m2 without non-condensable gas condition in steam.

Design and Test of 300W, 65K Pulse Tube

2004 ◽  
Author(s):  
Seth A. Potratz ◽  
Gregory F. Nellis ◽  
James R. Maddocks ◽  
John M. Pfotenhauer
Keyword(s):  
Heat Exchanger ◽  
Flow Behavior ◽  
Flow Characteristics ◽  
Frequency Measurement ◽  
Operating Conditions ◽  
Design Model ◽  
Pulse Tube ◽  
Tube System ◽  
Pressure Flow ◽  
Wide Range

This paper describes the design and preliminary experimental results for a large capacity (300W at 65 K) single-stage, Stirling-type pulse-tube. The regenerator, the critical component in the pulse-tube, was optimized via a parametric study accomplished using the REGENv3.2 program. The pulse tube system was subsequently designed using a 1st order model that calculates the pressure-flow characteristics of the system coupled with 2nd order models of the various internal loss mechanisms. An experimental pulse-tube system was fabricated based on this design; the pulse-tube apparatus allows simultaneous, high frequency measurement of instantaneous compressor piston position as well the instantaneous pressures at various locations in the system. In addition, the average temperatures along the regenerator, within the cold heat exchanger gas volume, on the cold heat exchanger surface, and along the pulse-tube are measured. This comprehensive set of measurements will allow a thorough evaluation and verification of the design model over a wide range of operating conditions including compressor stroke, frequency, charge pressure, and load temperature. This paper presents some preliminary experimental progress and compares the measured pressure-flow behavior with the design model predictions.

Turbulent Flow in a No-Tube-in-Window Shell-and-Tube Heat Exchanger: CFD vs PIV

2014 ◽  
Author(s):  
Salem Bouhairie ◽  
Siddharth Talapatra ◽  
Kevin Farrell
Keyword(s):  
Heat Exchanger ◽  
Mechanical Design ◽  
Tube Bundle ◽  
Fluid Dynamic ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Adiabatic Flow ◽  
Tube Heat Exchanger ◽  
Shell And Tube

A research-scale shell-and-tube heat exchanger housing a no-tube-in-window (NTIW) arrangement of tubes is analyzed using ANSYS® FLUENT. Three-dimensional, computational fluid dynamic (CFD) simulations of adiabatic flow in a periodic section of the exchanger were conducted. The numerical results were compared to particle image velocimetry (PIV) measurements in the window region where tubes are not present. As part of the study, the k-epsilon with scalable wall function, k-omega with shear stress transport (SST), Reynolds Stress (RSM), and Scale Adaptive Simulation (SAS) turbulence models were assessed. Each turbulence model showed some similarities with the recorded phenomena, but none fully captured the complexity of flow field outside of the tube bundle. Additional simulations of an entire NTIW exchanger model were performed to examine the flow behavior between the window and crossflow regions, as window momentum flux, ρu2, limits are a concern for safe mechanical design.

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