Heat Exchanger Research Articles

Data analysis for performance index of plate heat exchanger filled by ionanofluid-oil: parallel versus counterflow

Plate heat exchangers ensure their continued relevance and adaptability in meeting modern energy, environmental, and industrial demands. Innovations in this area significantly improve energy efficiency, reduce environmental impact, and enhance industrial processes. However, the ionanofluid significantly enhanced the thermal conductivity and heat transfer coefficient compared to conventional fluids. This study focuses on a three-chambered parallel plate heat exchanger (PHE) using cold ionanofluid (a mixture of graphene as nanoparticle and 1-ethyl-3-methylimidazolium thiocyanate ([C2mim][SCN]) as ionic liquid) in the top and bottom channels and hot oil in the middle channel. It aims to determine the most effective configuration for performance index (η) and energy efficiency, given the unique properties of ionanofluid. The governing equations of Navier–Stokes and energy balance are solved numerically using the finite element method. The impact of different Reynolds numbers (Re) and solid concentrations (ϕ) of nanoparticles on the fluid velocity and temperature fields is observed, and various related parameters are calculated. A comprehensive data analysis is conducted using the surface response method, including ANOVA, sensitivity analysis, and optimization testing. The counter and parallel flow designs achieve approximately 76.23% and 70.07% thermal enhancement at Re = 1, respectively. The optimal performance index occurs at (Re = 1, ϕ = 0.025), chosen to maximize predicted η (= 33972.3) and actual η (= 34020.03). The results indicate that the counterflow configuration consistently outperforms the parallel flow configuration regarding heat transfer efficiency. The counterflow configuration exhibited superior overall performance and provided a more uniform temperature distribution across the PHE. This research offers important insights into the application of ionanofluids in heat exchangers by comparing both parallel and counterflow setups. The study demonstrates high R2 values for the response function, highlighting its significance, and suggests practical implications for the optimization of heat exchanger designs in industrial settings.

Numerical investigation of segmental baffle design in shell and tube heat exchangers with varying inclination angles and spacing

This article explores the crucial function that Shell and Tube Heat Exchangers (STHE) play in a variety of industrial applications. This research uses a three-dimensional computational fluid dynamics (CFD) simulation to model turbulent fluid flow and evaluate the performance of different baffle angle configurations. The study evaluates performance indicators such as overall heat transfer coefficient (OHT), shell side heat transfer coefficient (HTC), pressure drop (PD), and PEC (Performance Evaluation Criteria), this study evaluates their effect on Segmental STHE performance. The findings indicate that the PD in the shell section rises by a range of 56.8–60.9% for baffles inclined 0° to 30°. Additionally, compared to the 0° inclined baffles, the 30° inclined baffles exhibit a greater OHT of 4.5–6%. The PEC values that are determined for each type of baffle are the most crucial aspect to take into account while selecting the optimal STHE. The 25° inclined baffles have been selected as the most advantageous baffles due to their improved performance, as seen by their different PEC values. In the subsequent stage of the study, researchers investigated how changing the quantity of superior baffles (inclined) affects the STHE’s efficiency. As the number of baffles was increased from 4 to 10, the OHT rose by 14.5–17% and the PD increased by 138.63–141.7%. This thorough simulation revealed that the STHE with the 8 inclined baffles had the highest PEC value and was therefore the most appropriate STHE.

Experimental investigation and simulation of a helical coil heat exchanger with hematite thermal reservoir

Experimental investigation and simulation of a helical coil heat exchanger with hematite thermal reservoir

Ocean stratification impedes particulate transport to the plumes of Enceladus

Water-vapour plumes erupting from Enceladus’ south pole provide a window into the properties of its subsurface ocean, a prime target in the search for life. However, the extent to which plume material represents conditions at Enceladus’ depths is unclear, because of its unknown ocean stratification, which may impede the transport of matter to the ocean top. Previous studies have found conflicting stratification regimes using differing parameter choices and model physics. Here, we build a comprehensive view of Enceladus’ ocean stratification and bottom-to-top transport timescale, across plausible ranges of salinity and tidally- and librationally-induced mixing, accounting for non-linearities in the equation of state for water, geothermal heating and ice-ocean freshwater exchanges. We use theoretical models verified with global ocean numerical simulations. We show that, under a steady state assumption for the ice shell, which requires melting at the poles, there is no parameter choice permitting an unstratified ocean from top to bottom there. As a result, potential hydrothermal products take at minimum 100s of years to reach the plumes. This suggests that either timescales of several months, inferred from Cassini observations, are incorrect, perhaps biased by alternative particulate transport mechanisms, or that Enceladus’ ice shell is not in a quasi-equilibrated state.

Critical Review of Corrugation in Tubular Heat Exchangers: Focus on Thermal and Economical Aspects

AbstractHeat exchangers (HXs) are crucial in transmitting thermal energy in various industrial and domestic applications. Efforts to improve the design of HXs over the years have resulted in heat transfer enhancement with the penalty of pressure loss (∆P). Researchers have implemented various methods to enhance heat transfer. These methods have been categorized based on the need for external power. Active heat transfer methods require external energy, whereas passive heat transfer methods operate without an external power source. Increasing the effective surface area for heat transfer or inducing turbulence through surface alterations can improve passive heat transfer, leading to secondary flow. Of all the surface alterations, the corrugated tubes are particularly significant for enhancing the heat transfer in a turbulent flow, as they result in a reasonable increase in ΔP. Apart from an increase in ΔP, the initial cost of corrugated tube HX is higher than that of simple HX. Therefore, one should not write off the economic analysis of any passive enhancement technique. Various applications increasingly use corrugation in systems like the primary and secondary heat transport systems of nuclear reactors, refrigeration, and other industries. This paper critically reviews thermal investigations for improving heat transfer and a comprehensive economic analysis of corrugated tube HXs.

Heat Exchange for Oscillator Strongly Coupled to Thermal Bath

Heat Exchange for Oscillator Strongly Coupled to Thermal Bath

A smoothed particle hydrodynamics approach for numerical simulation of tube heat exchangers

A smoothed particle hydrodynamics approach for numerical simulation of tube heat exchangers

COMPARATIVE ANALYSIS OF AIR CONDENSERS

BACKGROUND: The refrigeration industry is constantly developing new technologies that are being incorporated into the daily operations of commercial and industrial enterprises. A clear example of this is the emergence of microchannel air heat exchangers. They are characterized by high energy efficiency, material savings and minimal refrigerant content. Despite all the advantages, microchannel capacitors have a major drawback - they are poorly understood. Therefore, this work is devoted to the study of these heat exchangers, namely, an experimental study of heat transfer parameters and a comparative analysis of microchannel and plate-tube air condensers. AIMS: comparative analysis of microchannel and plate-tubular condensers in terms of temperature gradient and thermodynamic efficiency of refrigeration machines based on these capacitors. MATERIALS AND METHODS: the tasks were solved by conducting an experimental study of microchannel and plate-tubular capacitors in the laboratory, processing experimental data, assessing measurement errors, as well as thermodynamic analysis of the operating cycles of refrigeration machines based on air condensers. RESULTS: results were obtained on the temperature gradient, subcooling temperatures of the studied heat exchangers, and the values of the refrigeration coefficients of the machines were calculated. CONCLUSION: Studies have shown that the difference in condensation temperatures and the environment on a microchannel condenser is less than on a plate-tube heat exchanger. A refrigeration machine based on a microchannel unit has a higher coefficient of performance.

Case Study on Improving Vibration Failure of an Aircraft Heat Exchanger Brackets

Aircraft heat exchangers are devices used to cool the lubricating oil supplied to the gearbox and drive unit by utilizing low-temperature fuel/air. The bracket failure of heat exchanger was occurred while operating in a vibration environment. In this study, the cause of bracket crack was analyzed and an improvement method was proposed. From the results of scanning electron microscope(SEM) observation of the fracture surface, it was confirmed that the crack was initiated and propagated by resonance due to excessive vibration. Finite element analysis including modal and stress analysis of the heat exchanger structure was performed, and a vibration test was performed to compare the analysis and experimental results. Based on these results, an improved bracket thickness was obtained, and the safety factor was 9 or higher as the standard for the shear fatigue strength. The safety and durability of the improved bracket were verified through a vibration test.

Physical and Mathematical Modeling of the Process of Warming of the Greenhouse Soil

Statement of the problem. One of the main components of heat exchange in summer and seasonal greenhouses is investigated, i. e., the distribution of the temperature field in the heated soil. Results. Under the assumption of homogeneity of the semi-bounded space, which is a soil massif, the heat conduction equation with constant thermal and physical parameters is solved. It is shown that using the principle of superposition of solutions, as well as the properties of linearity and homogeneity of the equations, it is possible to apply (in order to study the dynamics of the temperature field in the closed ground of summer greenhouses) the method of heat waves with periodically changing boundary forces. In addition, the effectiveness of the application of mathematical physics methods using the dimension method in finding a partial solution to the heat conduction equation in order to model the process of soil heating in the conditions of a seasonal greenhouse is shown. Conclusions. Analytical expressions are obtained that allow us to determine the degree of heating of the soil layer of the summer greenhouse depending on the fluctuations of the temperature wave. For the soil of seasonal greenhouses, an expression was obtained for the change of the temperature gradient on the surface of the soil depending on the time of heating.

Collaborative Optimization of Stope Cooling and Geothermal Energy Exploitation for Backfill Embedded Heat Exchanger

Backfillembedded heat exchanger (BEHE) are used for stope cooling during the mining process and for geothermal energy recovery during the long-term heat extraction stage. This study develops a three-dimensional BEHE model to optimize the pipe arrangement, considering both the immediate requirements of stope cooling and the long-term objectives of geothermal energy exploitation. To evaluate the effects of geothermal energy extraction and stope cooling, heat extraction per meter and average temperature in the stope area are used as criterion parameters. The results indicate that the cooling efficiency is positively correlated with the number of pipe layers and pipe diameter, while it is negatively correlated with pipe spacing, interlayer spacing, and the distance from the bottom of the backfill-embedded heat exchanger (BEHE) to the cold radiation surface. Geothermal energy extraction, on the other hand, is positively correlated with the number of pipe layers, interlayer spacing, and the distance from the bottom of the BEHE to the cold radiation surface. Considering both objectives, the optimal pipe arrangement is determined to be PLS = 1.0 m, S = 500 mm, F = 3, D = 0.05 m, and DN = 50 mm. Additionally, based on a comprehensive analysis of extensive calculation results, an empirical correlation for heat extraction per meter as a function of pipe arrangement parameters was derived.

Unsteady MHD flow of tangent hyperbolic ternary hybrid nanofluid in a darcy-forchheimer porous medium over a permeable stretching sheet with variable thermal conductivity

Background This research investigates the unsteady magnetohydrodynamic (MHD) flow, heat, and mass transfer of tangent hyperbolic ternary hybrid nanofluids over a permeable stretching sheet. The study considers three types of nanoparticles—aluminum oxide (Al₂O₃), copper (Cu), and titanium oxide (TiO₂)—dispersed in a base fluid of ethylene glycol (C₂H₆O₂). This ternary hybrid nanofluid (Al₂O₃–Cu–TiO₂/C₂H₆O₂) has potential applications in cooling systems, biomedical uses for targeted drug delivery and hyperthermia treatments, heat exchangers, and polymer processing techniques like extrusion and casting. Methods The study examines the effects of various parameters, including the Weissenberg number, power law index, nanoparticle volume fraction, viscous dissipation, magnetic field, heat generation, nonlinear thermal radiation, temperature ratio, Joule heating, Brownian motion, thermophoresis, porous permeability, variable thermal conductivity, Eckert number, Prandtl number, Schmidt number, chemical reaction, velocity ratio, Forchheimer number, and unsteady parameters. The governing equations are transformed into similarity equations using appropriate transformations and solved numerically with the MATLAB BVP5C package. The results are validated against data from published articles to ensure reproducibility. Results The findings reveal that an increase in the Weissenberg and Forchheimer numbers reduces the velocity profile, while the temperature distribution increases. The variable thermal conductivity parameter (Γ) leads to a higher temperature profile, indicating improved heat transfer. Higher nanoparticle concentrations in the nanofluids and hybrid nanofluids result in enhanced skin friction, Nusselt number, and Sherwood number. Ternary hybrid nanofluids show the most significant improvement in heat transfer and thermal conductivity. Conclusions Ternary hybrid nanofluids significantly enhance heat and mass transfer, showing potential for applications in cooling systems, drug delivery, and polymer processing. The numerical results are consistent with previous research, confirming the reliability and reproducibility of the findings

Inverse Properties Estimation of Methanol Adsorption in Activated Carbon to Utilise in Adsorption Cooling Applications: An Experimental and Numerical Study

The precise estimation of influential parameters in adsorption is a key point in conducting simulations for the sensitivity analysis and optimal design of cooling systems. This study explores the critical role of a new type of granular activated carbon (GAC-208C) in adsorption refrigeration systems. By fitting experimental and numerical models to the thermophysical properties of GAC/methanol as a working pair, an advanced methodology is established for the thermal analysis of the adsorption bed, addressing the various operating conditions overlooked in prior studies. The physical properties of the studied carbon sample are determined in a laboratory using surface area and pore volume tests, thermal adsorption analysis, and weight loss. To determine the thermal properties of GAC/methanol, the adsorption process is experimentally tested inside an isolated heat exchanger. A three-dimensional (3D) model is created to simulate the procedure and then coupled with the particle swarm optimisation (PSO) algorithm in MATLAB. The optimal thermal parameters for adsorption are determined by minimising the mean square error (MSE) of the adsorption bed temperature between the numerical and experimental data. The laboratory studies yielded accurate results for the physical properties of GAC, including adsorption capacity, porosity, permeability, specific heat capacity, density, activation energy, and the heat of adsorption. The thermal analysis of the adsorption process identified the ideal values for the Dubinin–Astakhov equation constants, diffusion coefficients, heat transfer coefficients, and contact resistance. The numerical model demonstrated strong agreement with the experimental results, and the dynamic behaviour of pressure and uptake distribution showed good agreement with 1.2% relative error. This research study contributes to the improved estimation of adsorption parameters to conduct more accurate numerical simulations and design new adsorption systems with enhanced performance under different operating conditions.

Enhancing the Prediction of Flow Characteristics in an Inventive Plate Heat Exchanger Using Deep Learning Techniques

Abstract In modern energy research, minimizing fuel usage and harmful gas emissions are critical priorities. The application of advanced deep learning (DL) models to predict thermohydraulic characteristics of an innovative plate heat exchanger (IPHE) is investigated in this study. Building upon our prior work utilizing machine learning (ML) models, the focus is placed on predicting the Nusselt Number (Nu), friction factor (f), and performance (P) within a Reynolds number range of 500 to 5000. Advanced DL architectures—GRU, LSTM, and CNN—are utilized, resulting in substantial improvements in prediction accuracy and robustness. The LSTM model demonstrates superior performance, achieving R² scores of 0.9986, 0.9985, and 0.9968 for Nu, f, and P, respectively, significantly surpassing prior ML model results of 0.98, 0.979, and 0.9628. The findings highlight the capacity of DL models to capture complex, nonlinear relationships in thermohydraulic data, offering an enhanced approach to optimizing plate heat exchanger (PHE) performance. This work contributes to energy-efficient technological advancements, supporting global efforts to reduce environmental impacts while addressing rising energy demands.

Computer Simulation and Speedup of Solving Heat Transfer Problems of Heating and Melting Metal Particles with Laser Radiation

The study of the process of laser action on powder materials requires the construction of mathematical models of the interaction of laser radiation with powder particles that take into account the features of energy supply and are applicable in a wide range of beam parameters and properties of the particle material. A model of the interaction of pulsed or pulse-periodic laser radiation with a spherical metal particle is developed. To find the temperature distribution in the particle volume, the non-stationary three-dimensional heat conductivity equation with a source term that takes into account the action of laser radiation is solved. In the plane normal to the direction of propagation of laser radiation, the change in the radiation intensity obeys the Gaussian law. It is possible to take into account changes in the intensity of laser radiation in space due to its absorption by the environment. To accelerate numerical calculations, a computational algorithm is used based on the use of vectorized data structures and parallel implementation of operations on general-purpose graphics accelerators. The features of the software implementation of the method for solving a system of difference equations that arises as a result of finite-volume discretization of the heat conductivity equation with implicit scheme by the iterative method are presented. The model developed describes the heating and melting of a spherical metal particle exposed by multi-pulsed laser radiation. The implementation of the computational algorithm developed is based on the use of vectorized data structures and GPU resources. The model and calculation results are of interest for constructing a two-phase flow model describing the interaction of test particles with laser radiation on the scale of the entire calculation domain. Such a model is implemented using a discrete-trajectory approach to modeling the motion and heat exchange of a dispersed admixture.

Iron Oxide Scale Formation Mechanism and Anti-Corrosion Technology from Induction Remelting of Boiler Coating in Waste Incineration Power Plant

High-frequency induction welding technology represents the development direction of the high-temperature corrosion protection technology for the heating surfaces of the boiler “four tubes”. However, when the high-frequency induction coil heats and remelts the coating on the tube’s outer wall, the tube’s inner wall is also heated, causing an iron oxide scale to form on the tube’s inner wall. When the remelting temperature rises and the temperature of the tube’s inner wall exceeds 580 °C, three layers of oxide films, FeO, Fe3O4, and Fe2O3 are arranged in sequence from the substrate surface of the tube’s inner wall to the outside, with a thickness ratio of approximately 1:10:100. From the XRD spectra of tube iron oxide scale, it can be seen that the oxidation of the tube. The skin is mainly composed of Fe3O4, with a certain amount of Fe2O3 and trace amounts of FeO. The iron in the diffraction peak originates from the metal matrix. However, when the remelting temperature continues to rise and the temperature of the tube’s inner wall exceeds 580 °C, the oxide film begins to thicken significantly, that is, the oxide film begins to transform into an oxide scale. Under the continuous action of high-temperature induction remelting, the reaction between iron and oxygen is accelerated, but because the oxygen ions of water slowly diffuse through two outer layers of oxide films, with a low oxygen concentration. Although the FeO film is thin, it has a loose structure and numerous lattice defects, is unstable and easy to decompose, and easily peels off from the tube’s inner wall. For a pipe wall thickness of 5 mm, if the thinning rate of the inner wall caused by detachment reaches 0.8 mm/year, it is highly likely to cause pipe burst accidents within 4–5 years. The influence of the iron oxide scale on the performance of the tube’s inner wall was evaluated by testing indexes, such as surface hardness and decarburization layer depth. Although the oxide scale reduces the surface hardness of the tube’s inner wall, the surface decarburization layer is very thin, so the effect on the mechanical properties of the tube’s substrate is limited. The technology of inhibiting the formation of the iron oxide scale in induction remelting is briefly introduced. During the high-frequency remelting process of water-cooled walls, as the tube bank moves forward relative to the high-frequency heating coil, nitrogen protection is used to suppress the formation of oxide scale, effectively eliminating the troubles caused by high-frequency induction remelting and achieving the goal of improving the service life of the tube bank. This technology of the nitrogen protection method is used to inhibit the formation of iron oxide scale, not only inhibiting the formation of the iron oxide scale on the tube inner wall and the back of the tube bundle, with remarkable experimental results and broad application prospects.

Evaluating experimentally the viability of employing hybrid nanofluids as an operating fluid in a shell-and-tube heat exchanger.

The use of hybrid nanofluids (HNF) in heat transfer applications has become the subject of studies during recent periods. Its ability to transfer heat is superior to single nanofluids, and this has been proven in many research. Shell and tube heat exchanger is one of the most common types and are therefore always under research to improve their performance. This study is a practical study that examines the effectiveness of HNF in their use as operating fluids in shell-and-tube heat exchangers instead of traditional operating fluids. A laboratory heat exchanger was used to complete this study. A group of HNF (MWCNTs- Al2O3/water) was synthesized at different concentration rates ranging from 0.4 to 2%. Tests were conducted for Reynolds values in the range from 2500 to 12,560. By measuring the variables in the tests and calculating some factors the results showed that, in comparison between the use of HNF and distilled water, it was found that there is an increase in the value of the Nusselt number for the HNF over the distilled water in a range of 10- 28.5%. The effectiveness increased when using the HNF by up to 22.7% compared to distilled water. Through experiments, an equation was deduced to calculate the value of the Nusselt number. There is good agreement between the results of this research and previous literature.

Combined Flow and Temperature Nonuniformity in Compact Cross‐Flow Three‐Fluid Heat Exchangers

ABSTRACTCryogenic processes often involve the heat interaction of multiple fluids and are highly sensitive to even minor variations in operating conditions. Hence, flow and temperature nonuniformity adversely impact the performance of thermal systems, and their combined occurrence can be especially detrimental. The transient response and thermal effectivity of a cross‐flow three‐fluid heat exchanger are investigated while considering the flow and temperature nonuniformity at the inlet section. Four modes of combined flow and temperature nonuniformity are opted, which replicates the pragmatic situation existing in the working of heat exchangers, and the effectivity of the thermal system is evaluated by its alignment with the uniform flow mode. Flow nonuniformity is implicated in both the inlet section and within the core all along with the effect of fluid back mixing. The “Dankwert's” boundary condition is specifically used to account for the effects of axial dispersion within the fluids. The model incorporates longitudinal heat conduction in partition walls, with the “finite difference method” employed to solve the partial differential equations. To the best of our knowledge, the present study is the first attempt to analyze both the transient response and effectivity of three‐fluid heat exchangers under combined flow and temperature nonuniformity. It is learned that thermal effectivity is degraded by 31.5% and enhanced by 1% under flow nonuniformity mode QPQ and temperature nonuniformity mode 1 respectively. Under the combined mode of both, the effectivity settles down somewhere amid both and is found to be degraded by 8%. The higher NTU comes up with a sharp peak in temperature distribution, which makes the core more prone to cracks.

IIoT Implementation to Investigate the Heat Transfer Efficiency of a Concentric Corrugated Pipe Heat Exchanger

ABSTRACTThe Industrial Internet of Things (IIoT) plays a key role in industrial applications and manufacturing processes. Numerous technologies are implementing IIoT to monitor and control manufacturing processes, maintain reliability, and increase productivity. In this study, IIoT was used to demonstrate the heat transfer performance of a double‐pipe heat exchanger at the laboratory scale to provide research guidelines. Two types of inner pipes, smooth and corrugated pipes, were used in the experiment. In the experiment, the hot‐ and cold‐water mass flow rates were 9 and 10 L/m, respectively. The cold‐ and hot‐water temperatures were set at 20°C, 22°C, and 24°C and 35°C, 40°C, and 45°C, respectively. Equipment operation control and reading and recording of the experimental data were performed using PLC and IIoT platforms. The experimental results showed that heat exchange using corrugated pipes was more efficient than smooth pipes when considering the overall heat transfer coefficient, with an effectiveness of approximately 19%. However, corrugated pipes exhibited a 30% higher pressure difference compared to smooth pipes. This reveals that IIoT has been established and can be effectively applied to laboratory thermal solutions, allowing operators to read real‐time data at any time, both inside and outside the work area.

Modeling and simulation of entropy optimization in Darcy–Forchheimer flow of magneto-Ree–Eyring nanofluid with suction/injection and motile microorganisms

Recent studies indicate that nanofluids are crucial for solar heat exchange operations and solar energy collectors. Furthermore, the importance of energy and mass transfer in entropy creation is significantly increased in a number of industrial and engineering processes, such as mechanical power collectors, air conditioning, food processing, refrigeration, and heat exchangers. As a result of this advancement, this research is aimed to explore the comparative study on bioconvective Darcy–Forchheimer flow of an incompressible hydromagnetic Ree–Eyring nanofluid over a chemically activated expanding sheet in suction and injection cases while including the consequences of radiation, energy generation, and convective boundary conditions. Boundary layer approximation is utilized to represent this investigation’s primary partial differential equations (PDE). Then, using the appropriate transformation, the models are rebuilt into nonlinear ordinary differential equations (ODE). Utilizing the BVP5C inbuilt MATLAB package, the numerical solutions for this examination are established. Further, the graphical and tabular representations allow us to analyze the impacts of several relevant features on the microorganism’s density, concentration, entropy creation, velocity, temperature, friction factor, Sherwood, and Nusselt number distribution. The outcomes reveal that the velocity field of the liquid movement is declined by applying positive amounts of the Darcy–Forchheimer and magnetic parameters, respectively. Boosting values of the radiation, thermal ratio parameter, and temperature Biot number assist an increase in the thermal field. It reveals the augmented entropy generation with the rising values of bioconvection Lewis number and Brinkman number. Furthermore, the mass transfer rate increases with larger values of the Brownian parameter and chemical reaction parameter.