Shell And Tube Heat Exchanger Research Articles

Numerical analysis of thermal performance of waste heat recovery shell and tube heat exchangers on counter-flow with different tube configurations

This study investigates the effect of tube layout configurations on the hydraulic-thermal performance of shell-and-tube heat exchangers (STHXs) as waste heat recovery systems. The STHXs are triangular (30°, STHX-T), rotated triangular (60°, STHX-RT), and combined (STHX-C). Water at a temperature of 10 °C was circulated through a bundle of tubes inlet to recover waste heat from hot water at the temperature of 65 °C. Water was circulated through the shell inlet within the mass flow rate range of 0.5 ≤ ṁ ≤ 3.5 kg/s. ANSYS-Fluent was used to perform a three-dimensional computational study under steady-state conditions. The turbulence model, realizable k-epsilon, was adopted because of the possible transition from laminar to turbulence. The results were validated with the Kern correlation for shell-side heat transfer coefficient and pressure drop. The temperatures, pressure drop, velocity, and overall heat transfer coefficient for all the cases were compared. Temperature contours, pressure contour, velocity vector, and velocity contour were presented for flow visualization. When the simulation results of the different STHXs were compared, the results revealed that the STHX-T layout has the highest overall heat transfer coefficient of 2307.09 W/m2K. The maximum pressure drop of 242.42 Pa, highest temperature drop in the shell zone of 4.48 K, and highest temperature rise in the tube side of 6.67 K, followed by STHX-C and STHX-RT layout were obtained.

Thermo-Hydraulic Optimization of Shell and Externally Finned Tubes Heat Exchanger by the Thermal Efficiency Method and Second Law of Thermodynamics

The application aims to determine the thermal and hydraulic performance of externally finned, counter-flow, Shell, and Tube Heat Exchangers (STHE). The application refers to the cooling of machine oil flowing in the annular region, including non-spherical cylindrical nanoparticles of Boehmite Alumina. The oil inlet temperature is equal to 80 °C. Sea water is a coolant with an inlet temperature of 20°C. The main parameter in the optimization process is the number of finned tubes used for oil cooling. Another optimization factor is the number of heat exchanger units connected by hairpin. The number of fins per tube is fixed, equal to 34. The oil flow is set and equal to 4.0 kg/s. The inlet water flow varies, with a maximum flow of 5.0 kg/s. The quantities determined for analysis are: the thermal effectiveness, the actual and maximum heat transfer rates, the pressure drops caused in the tubes and by the flow in the annular region and fin system, the thermal and viscous irreversibilities, and the fluid outlet temperatures, and the thermodynamic Bejan number. It was determined that increasing the number of finned tubes from two to six tubes leads to better thermal and hydrodynamic performance. That is, it produces a favorable cost-benefit, to the detriment of the high viscous dissipation caused by the oil in the annular region. As an object of analysis, the inclusion of nanoparticles showed a significant improvement in thermal performance and an increase in viscous dissipation, with a slight decline in the Bejan number.

Multi-objective optimization of helical baffles in the shell-and-tube heat exchanger by computational fluid dynamics and genetic algorithm

Baffles are significant components to control shell-side flow distribution and enhance heat transfer in the shell-and-tube heat exchangers (STHXs). The helical baffles have become popular as a suitable alternative to segmental baffles The thermal-hydraulic performance in the shell and tube heat exchanger with helical baffles was modeled by the computational fluid dynamics (CFD) technique. The effects of the two main geometrical parameters including baffle pitch and baffle angle on heat transfer coefficient and pressure drop were studied. The CFD modeling results were validated with experimental data. The validated data were employed to develop predictive correlations. Finally, the optimum geometries of the investigated helical baffles were suggested using multi-objective genetic algorithm (MOGA) optimization. The optimum results presented a trade-off between heat transfer coefficient and pressure drop in the heat exchangers.

Shell and tube heat exchanger flexible design strategy for process operability

Traditionally, the shell and tube heat exchanger (STHE) design minimizes the total annual cost subject to allowable pressure drop. However, it is often insufficient when considering equipment limitations and uncertain disturbance factors. Design inefficiency or improper operation of overall process systems could potentially occur. A rigorous design strategy of STHE based on the flexibility index analysis method is proposed to address the above issues. The genetic algorithm with rigorous constraints is considered for the STHE design optimization. Simultaneously, the flexibility index (FI) is incorporated to quantify the uncertain factors of the STHE operation. The STHE load capacity and the corresponding uncertain disturbance factors affecting the STHE operability are evaluated. In addition, design workflows incorporating flexibility index are also discussed. Simultaneous consideration of the flexibility index in the optimization procedure can improve the STHE design operability under the expected range of disturbance factors and lower the total cost.

질량유량 변화에 따른 실물 크기 원통다관식 열교환기의 열전달 성능 평가

In this paper, a realizable k-ε turbulence model was used to analyze the mutual heat transfer of a full-scale three-dimensional shell and tube heat exchanger (STHEX) with a heat exchange length of 2,000 ㎜ when the mass flowrate flowing to the shell and the tube is changed into five types. The amount of heat lost from the shell and the amount of heat gained from the tube are almost identical when the mass flowrate of the shell and the tube increases, respectively, and are distributed non-linearly. In addition, the overall heat transfer coefficient increases non-linearly as the mass flowrate of the shell and the tube increases; it shows a value of about 420~670W/㎡·℃ at a given mass flowrate. On the other hand, it is judged that various approximation equations such as heat transfer amount can be important data that provide a lot of information in response to changes in the mass flowrate of the shell and the tube.

Effect of different pitches on the 3D helically coiled shell and tube heat exchanger filled with a hybrid nanofluid: Numerical study and artificial neural network modeling

The effects of using hybrid nanofluids and of helical coil pitch (λ) in a 3D shell and tube heat exchanger (STHE) are investigated. The algorithm used in this study is Phase Coupled SIMPLE and the method used is Eulerian. Nanofluid flow with Reynolds (Re) numbers of 10,000, 15,000, and 20,000, nanoparticles with volume fractions (ϕ) of 2 and 4%, and λ = 20, 25, 40, and 50 mm are investigated. The highest numbers related to the thermal index (Nu) and effectiveness occurred in the λ = 20 mm and the maximum ϕ and Re. In the case of λ = 20 mm, the maximum Nusselt number is 15.8%, 26%, and 45.3% more than that of 25, 40, and 50 mm, respectively. However, in the same case, in comparison between the ϕ = 4% and ϕ = 0, the Nu increases by 45.7%, 61.7%, and 76%. The present study shows that combining using hybrid nanofluids and changing the geometry of STHE, as an innovative approach can positively increase efficiency. Finally, the results are used for training an artificial neural network (ANN). In this regard, for finding the optimum neuron numbers in the hidden layer, the optimum feed-forward network is obtained to predict the efficiency of the material.

African vultures optimization algorithm for optimization of shell and tube heat exchangers

Abstract Nature-inspired optimization algorithms named meta-heuristics are found to be versatile in engineering design fields. Their adaptability is also used in various areas of the Internet of things, structural design, and thermal system design. With the very rapid progress in industrial modernization, waste heat recovery from the power generating and thermal engineering organization is an imperative key point to reduce the emission and support the government norms. However, the heat exchanger is the component applied in various heat recovery processes. Out of the available designs, shell and tube heat exchangers (SHTHEs) are the most commonly adopted for the heat recovery process. Hence, cost minimization is the major aspect while designing the heat exchanger confirming various constraints and optimized design variables. In this study, cost minimization of the SHTHE is performed by applying a novel metaheuristic algorithm which is the African vultures optimization algorithm (AVOA). Adopting the AVOA for the best-optimized value (least cost of heat exchanger) and the design parameters are realized, confirming all the constraints. It was found that the AVOA is able to pursue the best results among the rest of them and can be used for the cost optimization of the plate-fin and tube-fin heat exchanger case studies.

A Novel Step-by-Step Automated Heat Exchanger Network Retrofit Methodology Considering Different Heat Transfer Equipment

Improving the energy efficiency in heat exchanger networks (HENs) remains a significant industrial problem, specifically in energy-intensive operations. A particular method for such an objective is the modification of HENs at the equipment-use level, where structural changes take place and units within the network are moved, replaced and/or removed. This practice is usually known as retrofit. The objective of a retrofit is to maximize the heat recovery using the minimum modifications possible and minimum retrofit cost. Traditional retrofit techniques would normally consider one type of heat exchanger (based on the original network) with no additional design features (i.e., heat transfer enhancement technologies). The expansion of such alternatives is limited by practical use and availability of theoretical methods. In this context, the inclusion of high-performance heat exchangers such as plate heat exchangers (PHEs) has not been widely explored, even when their design and operational advantages are known. In this work, a new step-by-step automated HENs retrofit approach based on Pinch Analysis is proposed. The approach is possible to identify the best modification, its location within the network, and its cost simultaneously. Moreover, to increase energy savings, this work presents a strategy that seeks to utilize high efficiency heat exchangers such as plate heat exchangers for retrofit. A distinctive feature of this new method is the ability to handle different minimum approach temperatures, given the different types of exchangers, within the optimization of HENs. Three cases are studied using this methodology to quantify the potential benefits of including PHEs in HEN retrofits, via the analysis of the retrofit cost. Results are compared with a baseline consisting in the same network, where only Shell-and-Tube-Heat-Exchangers (STHXs) are used. In addition, the results demonstrate that this methodology is flexible enough to be applied in a wide range of retrofit problems.

Numerical Simulations of Shell and Tube Heat Exchanger with Segmental, Trefoil and Segmented Trefoil Baffles for Performance Comparison

Shell and tube heat exchangers (STHX) are the most abundantly used heat exchangers in the industry. Baffles are the most important component involved in improving the thermohydraulic performance of STHXs. In this study, we propose a novel segmented trefoil baffle (STB) formed by imposing trefoil holes on segmental baffles (SGB). Numerical simulations have been conducted using ANSYS FLUENT 19.2 for SGBs, trefoil hole baffles (THB), and STBs at various mass flow rates to compare the heat transfer coefficients, pressure drop, thermohydraulic performance, and shell side flow distribution. Results indicate that for almost the same heat transfer coefficient, the pressure drop is significantly less for the STBs compared with the SGBs. A study of the flow field revealed that large dead zones, typical of SGBs, reduce significantly when STBs are used. Similarly, the recirculation zones, reported for THBs also decrease by incorporating the STBs. The thermohydraulic performance is enhanced by 41% and 235% compared to SGBs and THBs respectively by using the STBs. An increase in the number of baffles from 6 to 10 further enhanced the advantage of STBs over the segmental baffles from 41% to 57%. The inclusion of baffles to shell and tubes clearances does not affect the superior thermohydraulic performance of STBs over SGBs.

Development of an OpenFOAM solver for numerical simulations of shell-and-tube heat exchangers based on porous media model

• An innovative OpenFOAM solver of shell-and-tube heat exchangers was developed. • The coupling between porous media and drift flux two phase model was realized. • The feasibility of new solver was validated by two international benchmarks. • The key three dimensional thermal parameters of heat exchanger were achieved. As one of the most widely used types of heat exchangers, the shell-and-tube heat exchanger (STHX) offers the advantages of being low-cost, easy to clean, and highly reliable under high pressure and temperature conditions. Generally, a large number of tube bundles are used in the STHX to increase the heat transfer capacity. The three-dimensional (3D) two-phase flow simulation of the STHX is made exceedingly difficult if the tube bundle region is full-size modeled. Therefore, simplified models and approaches are required to meet the urgent demands of STHX engineering numerical simulation, especially for 3D analyses. Herein, we have developed an OpenFOAM solver “PorousDriftFoam” suitable for the two-phase flow and the boiling heat transfer numerical simulation of the STHX. The porous media model was applied to simplify the tube bundle region and the drift-flux model (DFM) was adopted in the two-phase flow computational fluid dynamics (CFD) simulation for the STHX. The heat transfer tubes are regarded as the solid region of porous media, while the shell side is considered the fluid region. We calculate the coupling heat transfer between the tube and the shell sides and consider the resistance introduced by the heat transfer tubes and support plates in the STHX. Two international benchmarks, the FRIGG test and the MB-2 experiments, were selected to fully validate the solver. For the FRIGG experiment, the predicted void fraction stands in good agreement with the experimental data, with an average absolute error of 0.07 and an average relative error of 13.3%. For the MB-2 experiment, the predicted values of pressure drop and temperature fit well with the experimental data. The developed solver could be applied in the 3D two-phase flow and heat transfer numerical simulation of a typical STHX in the industry.

Economic cost and efficiency analysis of the employment of inserting rods with helical fins in a shell and tube heat exchanger under magnetic field and filled with nanofluid

Present numerical investigation studies the influence of inserting rods with helical fins in a shell and tube heat exchanger (ShT-HEX) under magnetic field (MF) and filled with two-phase nanofluid (NF) on the thermal–hydraulic performance (THP). The goal of the present article is to study the influence of different geometrical factors of fins, different Re, various MFs and also different nanoparticles concentrations on the THP of Newtonian NF flow under MF in a novel HEX using the finite volume method. Also, an economic analysis is done with the interesting parameter heat flux to reduce the weight of the HEX. It was found that the novel configuration with b = 100 mm and a = 23 mm filled with MgO-SAE10 NF at φ = 1.500% under the MF of B = 0.5 T has the optimum characteristics with the q“ = 98.08 W/m 2 and 143.60 W/m 2 at Re = 8,000 and 20,000, respectively. Based on obtained results, the costs of manufacturing of novel model can be 88% of the basic model. Therefore, the economic enhancement is done in this investigation using ANSYS-Fluent and SolidWorks software.

Investigation on Shell and Tube Heat Exchanger by Using CFD

In this study, a detailed technique is built to examine the effectiveness of a shell and tube heat exchanger (STHE) with 35% baffle cuts (Bc) and variable numbers of baffles. Water was used as the working fluid in CFD simulations of a single pass and single tube heat exchanger. For this simulation investigation, a counterflow approach is used. The commercial CFD software package ANSYS-Fluent was utilized for computational analysis of STHE, and distribution of temperature was obtained due to the usage of copper and aluminum materials. In this research, the shell and tube heat exchanger was studied with the number of baffles of four, and six pieces by varying the mass flow rate value which is 0.5,0.8, and 0.9. From this research, it was found that the highest total heat transfer rate and highest heat transfer coefficient is produced by copper with Six baffles at 0.9 mass flow rate.

Enhancement of heat transfer in shell and tube heat exchanger using mini-channels and nanofluids: An experimental study

This study aimed to experimentally investigate the effects of Al2O3-water nanofluids with six different volume concentrations (0.02%, 0.1%, 0.2%, 0.4%, 0.6%, and 0.8%) instead of water as working fluid on heat transfer and pressure drop on the tube side of a mini-channel shell and tube heat exchanger (MC-STHE). The shell-side hot fluid flow rate was kept constant at 180 L/h, while the flow rate of the tube-side cold fluids ranged from 125 to 600 L/h. The convective heat transfer coefficient (CHTC) of the nanofluids increased in the transition and turbulent regions. The nanofluids also extended the transition region. The nanofluids had higher friction factors than water. The nanofluids had an optimal volumetric concentration and a flow rate of 0.4% and 375 L/h, respectively, at which the CHTC enhanced by 49%, while the friction factor increased by 21% compared to water. Compared to macrotube heat exchangers, the CHTC enhanced 3 to 7 times with the combined effect of the mini-channels and nanofluids in the shell-and-tube heat exchanger (STHE). Consistent with earlier studies (maximum TEF of 1.8), the thermal enhancement factor (TEF) for the optimal volumetric concentration Al2O3-water nanofluid in the MC-STHE was 1.6 at most under the same hydrodynamic conditions. The performance evaluation criterion (PEC) and the efficiency evaluation criterion (EEC) showed that there was no point (not enhancement) in using nanofluids instead of the base fluid (water) in the MC-STHE.

Performance characterization of a solar-powered shell and tube heat exchanger utilizing MWCNTs/water-based nanofluids: An experimental, numerical, and artificial intelligence approach

In the present work, Multi-Wall Carbon Nanotubes (MWCNT)/water nanofluids are used to increase the performance of a shell and tube heat exchanger (STHX) while reducing energy consumption and overall cost. MWCNT/water with 0.3% and 0.05% volume fractions were studied for stability and thermophysical characteristics. At a 0.3% volume fraction, a substantial improvement in the heat transfer coefficient of around 31.08 % was found compared to the base fluid. Experiments were conducted on STHX, and the results show that using nanofluid at a volume fraction of 0.3% improves heat exchanger efficacy by 5.49% compared to the base fluid. Good agreement was obtained between experimental and analytical results. Furthermore, a numerical model was developed using ANSYS commercial software to study the inclusion of semicircular baffles with nanofluid. Results suggest that MWCNT/water nanofluid at 0.3% volume fraction, along with semicircular baffles, enhanced the overall efficacy of the shell and tube heat exchanger by 15.4%, according to numerical data. Furthermore, comparisons between the proposed heat exchanger (STHX) with previous literature was also carried out. Results suggest a notable enhancement of 7% and 12.4% on heat transfer coefficient and overall efficiency was achieved compared to the previous literature. The experimentally acquired temperature variation data was utilized to create an artificial intelligence-based prognostic model. The multilayer perceptron type artificial neural network (MLP-ANN) was employed to map and forecast the thermal performance of MWCNT nanofluids on the tube side and water on the shell side. The tube side model had excellent R and R2 values of 0.998 and 0.996, while the shell side model had R and R2 values of 0.994 and 0.988, indicating a robust predictive model. The Kling-Gupta efficiency of the prediction model as 0.9936 and 0.9865 for tube side and shell side models, respectively, further confirms the MLP-ANN based model as an efficient prognostic model. A life cycle study was additionally performed to assess the framework's total energy usage, carbon footprint emissions, and cost over a 25-year life expectancy. The studies eventually indicated that the solar-assisted STHX is both cost-effective and environmentally beneficial.

Ecological optimization and LCA of TiO2-SiC/ water hybrid nanofluid in a shell and tube heat exchanger by ANN

The current study estimates the environmental impact and cost model for the early-stage design of a shell and tube heat exchanger (STHE). Additionally, the lifecycle analysis (LCA) compares the effects of use of nanofluid in the chemical processing industry to increase the effectiveness of the heat transfer to the typical STHE system. Nanofluids increase heat transfer, as evidenced by the results of the experiments. The Nusselt number and pressure drop were both increased by roughly 65% and 8%, respectively, using 0.5 vol% of TiO2-SiC/water hybrid nanofluid compared to water as coolant. The ecological impact of STHE was estimated as s attribute of Ecological (EF) and total cost estimation function using artificial neural networks (ANN). Finally, the IdematLightLCA (2.8.6 version) software was used to calculate energy content, Carbon footprint, and cost over the lifespan of the baseline. The results show that nanofluid-based STHE has an average payback period considerably longer than typical coolant systems but saves superior economic value at the end of its lifetime. According to the findings, the suggested novel method is both cost-effective and environmentally feasible.

Investigation on Shell and Tube Heat Exchanger by Using CFD - A Literature Review

In this study, the Shell and tube heat exchanger (STHE) was studied with variations in baffle types. Various baffle types and angles allow a wide range of possibilities. Baffles can be configured in a variety of ways to achieve better results at various phases of their use. Many additional improvements can be made to STHXs to improve performance. In order to optimize the design of STHE, material selection is critical. The distribution of temperature was produced using the Computational Fluid Dynamic (CFD) approach in the ANSYS FLUENT program due to the use of various materials. This publication compiles a list of successful changes that have left enough traces for future research.

Modeling of Supercritical CO2 Shell-and-Tube Heat Exchangers Under Extreme Conditions: Part II: Heat Exchanger Model

Abstract Heat exchangers play a critical role in supercritical CO2 Brayton cycles by providing necessary waste heat recovery. Supercritical CO2 thermal cycles potentially achieve higher energy density and thermal efficiency operating at elevated temperatures and pressures. Accurate and computationally efficient estimation of heat exchanger performance metrics at these conditions is important for the design and optimization of sCO2 systems and thermal cycles. In this paper (Part II), a computationally efficient and accurate numerical model is developed to predict the performance of shell-and-tube heat exchangers (STHXs). Highly accurate correlations reported in Part I of this study are utilized to improve the accuracy of performance predictions, and the concept of volume averaging is used to abstract the geometry and reduce computation time. The numerical model is validated by comparison with computational fluid dynamics (CFD) simulations and provides high accuracy and significantly lower computation time compared to existing numerical models. A preliminary optimization study is conducted and the advantage of using supercritical CO2 as a working fluid for energy systems is demonstrated.

Integrated software suite for heat recovery networks and equipment design

Heat Integration (HI) with heat exchangers requires intimate knowledge and intensive calculations to set energy-saving targets to achieve the goal of efficient energy utilisation. The Shell and Tube Heat Exchanger (STHX) Design Software Module, or SPIL-HX package developed by the SPIL team, offers features that support engineers to design and rate original STHXs, STHXs coupled with the shell-side enhancement technologies, i.e., with segmented baffles and with helical baffles. This software tool also provides design solutions for the Waste Gas Compact Thermal Oxidiser (WGCTO), identifying the unit design capable of simultaneous combustion and heat exchange for waste gases. SPIL-HX package is also capable of automatic Heat Exchanger Network (HEN) synthesis and retrofit. With the built-in algorithm, the software can provide the optimal solution for HI, which significantly reduces operating, capital, and design costs. A user-friendly interface facilitates the use of the developed software.

Effect of helical baffles and water‐based Al2O3, CuO, and SiO2nanoparticles in the enhancement of thermal performance for shell and tube heat exchanger

AbstractIn this study, Shell and tube heat exchanger (STHX) with 22% cut segmental baffles and helical baffles with 20°, 30°, 40° inclination angles are considered for three‐dimensional CFD analysis using the ANSYS FLUENT tool to investigate the performance of STHX. OHTC and comprehensive performance index are higher for 40° helical baffles when compared to segmental baffle and 20°, 30° helical baffle heat exchangers with water as working fluid. Hence, further investigations are carried out for 40° helical baffle heat exchangers. Numerical investigations are extended with nanofluids (Al2O3, CuO, and SiO2) at 1%, 3%, and 5% volume concentrations for each nanofluid. Under the same mass flow rates, 40° helical baffles with Al2O3nanofluid as working fluid provided better heat transfer rates when compared to the other two nanofluids and base fluid. Also, the authors noticed that the 5% volume (vol) concentration nanofluids provided better heat transfer enhancements when compared to 1%, 3% volume concentrations, and base fluid. Enhancements (10.33%–8.24%) from lower to the higher mass flow rate in 40° HB with Al2O3nanofluid at 5% volume concentration are observed when compared to water as base fluid.

EFEK KONFIGURASI BAFFLE PADA HEAT EXCHANGER TYPE SHELL AND TUBE SEBAGAI PEMANAS BAHAN BAKAR BIODIESEL B20

B20 is a fuel that is widely used for combustion systems in diesel engines, especially in Indonesia. Apart from having the advantages, biodiesel B20 also has various disadvantages that affect the performance of diesel engines such as those that have a higher flash point than diesel so that biodiesel is more difficult to burn and has a high viscosity which causes less good atomization of fuel and eventually causes deposits in combustion chamber. One or the solution to the problem is that it can be done carefully. The aim of this research is to make a Shell and Tube Heat Exchanger (STHE) by including the insulation in it to improve the heat exchange performance. The method applied in this research is an experiment by testing the performance of the heat exchanger using a cooling water jacket. Some of the equipment used is a diesel engine from the Mitsubishi Diesel Engine, Type 4d35, 4 cylinder, 75 HP. Data were collected at a constant rotation of 1500 rpm at no load. The results showed that the higher the cooling water temperature of the jacket, the higher the biodiesel temperature. With a cooling water jacket temperature of 83oC, it can heat biodiesel at 74.8oC. Keywords : B20 Fuel Oil; Diesel Engine; Heater; Heat Recovery; Jacket Cooler