Plate-fin Type Research Articles

Parametric design optimization and thermodynamic analysis of plate fin heat exchanger for helium liquefaction system

The plate-fin heat exchanger is one of the most important components of helium liquefaction system as it recovers cold energy from helium gas in the cold box. Because of larger heat transfer surface area and compact geometrical configuration, plate-fin heat exchangers are widely used. The design of heat exchanger using helium as a cryogenic fluid needs high thermodynamic performance with minimum pressure drop which particularly requires the optimization of dimensional array and its geometrical configurations. In this regard, a parametric investigation was performed to compute the effective geometrical parameters and its effect on thermodynamic (effectiveness and log-mean temperature difference) performance has been discussed in detail. The present study aims to design optimization and thermodynamic performance evaluation of plate-fin type heat exchangers used in helium liquefaction systems. The developed helium liquefaction model has been simulated for the most critical liquefier with and without liquid nitrogen precooling, mixed mode, and refrigeration mode. Each component of the liquefaction model has been technically and thermodynamically analyzed and, in particular, four plate-fin heat exchangers have been considered and designed accurately using Aspen EDR®. Initially, the sensitivity analysis was carried out to characterize the most significant geometrical parameters (fin thickness, height, number and arrangement of layers, frequency, and fin type) and their effect on thermodynamic performance and pressure drop. After that, the artificial intelligence model was used to determine the optimal range of such geometrical variables in which the heat exchanger has maximum effectiveness and log mean temperature difference. Finally, the operating conditions obtained from cycle modeling and optimized geometrical datasets have been applied in commercial simulation software Aspen EDR® for plate-fin heat exchangers design. Finally, a comparative thermodynamic analysis has been carried out to determine the performance of all the designed heat exchangers operating at four different modes (boundary conditions).

Energy and exergy analysis of microchannel central solar receivers for pressurised fluids

Within the new generation of advanced central solar receivers, microchannel pressurised gas receivers are emerging as reliable and efficient alternatives to operate at high temperatures and pressures. This paper presents an optimisation and comparative analysis of different compact plate-fin type structures, constituting the receiver’s absorber panels, classified according to the type of fin arrangement inside: plain rectangular, plain triangular, wavy, offset strip, perforated, and louvred fin. A versatile thermo-fluid receiver model is implemented, allowing simple variation of characteristic geometric parameters of each structure. Exergy efficiency is chosen as the optimisation function, as it considers both heat and pressure losses.The framework of the analysis is set by the receiver’s boundary conditions, operating at the design point conditions of a solar thermal power plant. For each compact structure, the optimal configuration is determined, providing interesting findings that have not been reported in the state-of-the-art to date. Although all geometries show good thermal performance, the perforated and plain rectangular configurations demonstrate the best exergy efficiencies of 59.21% and 58.80%, respectively, favouring taller and narrower channels. This analysis methodology could be seamlessly extrapolated to other gases and working conditions, owing to the thermo-fluid model’s versatility, to reveal the optimal configuration for each case.

Heat Transfer Performance of Plate Fin and Pin Fin Heat Sinks Using Al2O3/H2O Nanofluid in Electronic Cooling

The thermal management of electronic devices has become a major problem in recent years. Therefore, there is a growing need for research on many new materials and innovative fluids due to the developing technology and increasing cooling need in electronic systems. In this paper, heat transfer from a plate fin and pin fin type heat sinks that were placed in a water block that are used in electronic systems was investigated. A base fluid (pure water) and 0.1% mass concentration Al2O3-H2O nanofluid were used as cooling fluids. The experiments were carried out for volumetric flow rates varying between 100 and 800 mL/min and heat flux values of 454.54 W/m2 and 1818.18 W/m2. The results demonstrated that the Al2O3-H2O nanofluid on the empty surface provided a maximum improvement of 10.5% in heat transfer compared to the base fluid. In the use of plate finned heat sink, the maximum amount of improvement in heat transfer compared to the empty surface was obtained approximately 64.25% for the base fluid and 82.8% for the nanofluid. A similar comparison was made for the pin-fin heat sink, a maximum thermal improvement of 56.4% in the base fluid and 70.27% in the use of nanofluid was determined.

Deep learning for both broadband prediction of the radiated emission from heatsinks and heatsink optimization

Heatsinks have quasi-antenna behavior in many cases and cause interference both at the system level and at the PCB design level. Therefore, determination or prediction of both resonance frequencies and maximum radiated emission are crucial at any design step. In this paper, as a novelty, in 2–8 GHz band, a model based on deep learning is developed to predict resonance frequencies in parallel plate-fin type heatsinks. Parameters taken into account are the number of fins, the width, length, and height of the heatsinks. 3888 heatsinks with different sizes are modeled to prepare data set and the Grey Wolf Optimizer algorithm (GWO) is utilized to optimize the heatsink parameters. Consequently, while this model obtains outputs for certain inputs, the optimization algorithm procures certain inputs for these outputs. Furthermore, the predicted and optimized results are compared with the simulation and measurement results. The proposed model successfully works according to the measurement and the proposed model results since R2 values are 0.96, 0.98, 0.97, and 0.99 for f1,f2,REmax1, and REmax2, respectively. The results are good agreement and R-squared values of resonances (f1,f2) and the maximum radiated emissions (REmax1,REmax2) are quite acceptable considering the sophisticate of the proposed model.

Effect of Fin Type on Performance of Compact Heat Exchangers with Mini-Channel

A comparative investigation is carried out to reveal the effect of plate-fin type variation on the performance of compact heat exchangers (CHX) with a mini-channel flat tube. The CHX prototypes with plain, louver, and offset strip fins with the same frontal area are tested in the same air tunnel under the same experimental conditions to provide a better comparison. Besides the typical performance measures namely Colburn j-factor, friction, and volume goodness factors, some rarely chosen measures are considered as well, such as the core volume goodness factor to evaluate the performance of the prototypes from all aspects. Due to the nature of the mini channel flat tubes, the flow depth is very narrow and one of the targets is to understand the importance of the fin-type on the performance in such a short flow depth. As regards to the outcomes, the CHX with plain fin shows better performance when it is evaluated by the typical approaches which is presented with respect to Reynolds number but when the compactness is considered in performance evaluation, CHX with louver fins achieves higher heat transfer indexes than other fin geometries.

Parametric Study of the Radiated Emission From the Plate-Fin CPU Heatsink at 2–8 GHz

This study proposes an approach to minimize the electromagnetic radiated emissions (RE) from the plate-fin type heatsinks, and the proposed approach is based on the parametric analysis using measurement and simulation results. In the parametric analysis, width, length, height, number of fins, base height, and fin thickness on electromagnetic interference effects are taken into account in the range of 2–8 GHz (S-C band). Simulations are held as a first step, and that is followed by the production of them. The next step is conducting regular standard measurements in an anechoic chamber to validate the simulation results. According to the results, first, parameters such as length, fin height and width are more effective on radiated emission than the others with an amount of change in RE of 1–6 dBmV/m. Second, these three parameters are effective in 52%, 73%, and 38% of the 2–8 GHz band, respectively. The length of the heatsink is recommended in the widest frequency band (73%). Lastly, when the effects of these three parameters on RE are examined, width is the most efficient with 5–6 dBmV/m.

Detailed Design Optimization of Three-Fluid Parallel-Flow Plate-Fin Heat Exchanger Using Second Law Analysis

Abstract Compact parallel-flow three-fluid heat exchanger (TFHX) of plate-fin type is optimized for attaining the minimum entropy generation unit. Four different types of plate-fins (plain rectangular, offset strip, corrugated louvered, and wavy fin (WF)) which are embodied within heat exchanger have been selected for the study under both cocurrent and countercurrent flow arrangements. The range of the decision variables are 0.3≤ma, mb, mc≤3, 0.1≤Ø≤0.95, 0.1≤Lx, Ly≤2, 0.015≤H≤0.033, 100≤n≤700, 0.0001≤tf≤0.0002, 0.001≤l≤0.009, 0.01≤Lwav≤0.09, and 0.001≤A≤0.005. Genetic algorithm is selected as an optimization tool that is apt in handling various continuous and discrete variables and the problems with the complexities in the objective function as well as in constraints. Validation of the optimization model is carried out by comparing the optimum results with that obtained from the experiments, particle swarm optimization (PSO) (under without heat duty constraint), and graphical method (under with heat duty constraint). It is observed that for a specified heat duty (180 kW) and given operating conditions, corrugated louvered fin (CLF) with countercurrent flow arrangement offers the minimum entropy generation among all. It is riveting to learn that the optimum results occur for most of the considered cases when the flowrate of the central hot fluid is lower than that of the adjacent fluids. At fixed Re = 3000 for all the fin types, off-set strip fin is the most favorable one, and plain rectangular fin (PRF) offers the worst solution comparatively.

Performance analysis of plate-fin heat exchanger used for case drain oil cooling application in variable displacement pumps

Variable displacement pumps are commonly employed in fluid power equipment. In applications involving variable displacement pumps, overheating of oil is a frequently encountered problem necessitating an effective oil cooling solution. In this work, the thermo-hydraulic performance analysis of an air blast hydraulic oil cooler, which is a compact heat exchanger (Brazed Aluminium Plate-Fin type) with surface heat enhancement feature in the form of rectangular offset strip fins is presented. The performance models available in the literature present correlations for f and j factors limited to a particular surface geometry and Reynolds number Re range. In the present work a detailed theoretical thermo-hydraulic analysis of an existing heat exchanger is presented using models available in the literature and also experimentally validated using a developed test-rig. The performance parameters derived from f and j factors like exchanger effectiveness, heat transfer coefficients and pressure drop are amply addressed. It was found that, cooler effectiveness varied only slightly with increasing oil inlet temperatures; whereas effectiveness decreased with increasing flow rates. The heat transfer rates increased with increasing oil flow rates and also with increasing oil inlet temperatures. The pressure drop on the oil side was found negligible.

Analysis of uncertainties in compact plate-fin recuperators for microturbines

The current study aims to perform a stochastic analysis on microturbine compact recuperators to evaluate the impact of uncertainties in design parameters on their cost and volume, by using two different probabilistic approaches: Monte Carlo (MC) and Response Sensitivity Analysis (RSA).These two methods have been developed in Matlab® and then coupled with CHEOPE (Compact Heat Exchanger Optimisation and Performance Evaluation) software, which allows to analyze two different types of recuperators, used in microturbine applications: the furnace-brazed plate-fin type and the welded primary surface type. This paper focuses on an analysis of plate-fin type recuperators, for which the cost function adopted was tuned and verified in a previous study.Three main parameters of the recuperator have been considered as uncertain: effectiveness, hot side and cold side pressure drops. The uncertainties associated with these three parameters are based on industrial knowledge. The aforementioned stochastic methods have been used to propagate such uncertainties on the relevant outputs, such as cost and volume, allowing us to evaluate the least expensive and the most compact recuperator among those analysed.

Performance Analysis in Cross Flow Plate Fin Type Heat Exchanger

Performance Analysis in Cross Flow Plate Fin Type Heat Exchanger

Optimal Configuration of Vortex Generator for Heat Transfer Enhancement in a Plate-Fin Channel

Heat transfer is a naturally occurring phenomenon and its augmentation is a vital research topic for many years. Although, vortex generators (VGs) are widely used to enhance the heat transfer of plate-fin type heat exchangers, few researches deal with its thermal optimization. This work is dedicated to the numerical investigation and optimization of VGs configuration in a plate-fin channel. Three-dimensional (3D) numerical simulations are performed to study the effect of angle of attack and attach angle (angle between VG and wall) and shape of VG on the fluid flow and heat transfer characteristics. The flow is assumed as steady-state, incompressible, and laminar within the range of studied Reynolds numbers (Re = 380–1140). Results are presented in the form average and local Nusselt number and friction factor. The effect of attach angle is highlighted and the results show that the attach angle of 90 deg may not be necessary for enhancing the heat transfer. The flow structure and heat transfer characteristics of certain cases are examined in detail. The parameters of VG are then optimized for maximum heat transfer and minimum pressure drop. The three independent design parameters are considered for the two objective functions. For this purpose, computation fluid dynamics (CFD) data, response surface methodology (RSM) and a multi-objective optimization algorithm (MOA) are combined. The data obtained from numerical simulations are used to train a Bayesian-regularized artificial neural network (BRANN). This in turn is used to drive a MOA to find the optimal parameters of VGs in the form of Pareto front. The optimal values of these parameters are finally presented.

Simulation Model of Plate-Fin Wet Air Heat Exchanger Based on Enthalpy Parameter Matching Method

Plate-fin heat exchanger is widely used. In this paper, the plate fin type heat exchanger is modeled and calculated by enthalpy parameter matching method. The calculation results show that the enthalpy parameter matching method has high accuracy and can be used for the calculation of the engineering calculation for the dry heat exchanger and the wet air heat exchanger.

평판-휜 열교환기의 열-수력학적 성능에 대한 고속 바이패스 영향의 수치적 연구

The high-speed bypass effect on the heat exchanger performance has been investigated numerically. The plate-fin type heat exchanger was modeled using two-dimensional porous approximation for the fin region. Governing equations of mass, momentum, and energy equations for compressible turbulent flow were solved using ideal-gas assumption for the air flow. Various bypass-channel height were considered for Mach numbers ranging 0.25-0.65. Due to the existence of the fin in the bypass channel, the main flow tends to turn into the core region of the channel, which results in the distorted velocity profile downstream of the fin region. The boundary layer thickness, displacement thickness, and the momentum thickness showed the variation of mass flow through the fin region. The mass flow variation along the fin region was also shown for various bypass heights and Mach numbers. The volumetric entropy generation was used to assess the loss mechanism inside the bypass duct and the fin region. Finally, the correlations of the friction factor and the Colburn j-factor are summarized.

Application of Grenade Explosion Method Optimization for Plate-Fin Type Heat Exchanger (PFHE)

Application of Grenade Explosion Method Optimization for Plate-Fin Type Heat Exchanger (PFHE)

고고도 장기체공 무인기용 수소 왕복 엔진의 다단터보차저용 인터쿨러 설계 및 해석

Intercoolers for multi-stage turbocharger of the hydrogen reciprocating engine for HALE UAV are installed for reducing the charged air inlet temperature of the engine. The intercooler is air to air, cross flow, plate-fin type and the fin configuration is offset-strip fin which is referenced from the heat exchanger of the ERAST. Most of HALE UAV’s cruising altitude is 60,000 ft and the density of air for this altitude is very low compared to sea level. Therefore the required heat transfer area for the HALE UAV is about three-times bigger than the sea level. Consequently, it is essential to design to meet the required efficiency of intercooler in the range of not excessively growing the weight of the heat exchanger. The quasi-one dimensional heat transfer design/analysis for satisfying the requirement of the engine are written in this paper. The numerical analyses for estimating the coolant flow rate of the engine bay and pressure loss in the header and core are also summarized.

Numerical Simulation of Relationship Between Member Dimension and Weld-induced Stress in Plate-fin Type Heat Exchanger

Numerical Simulation of Relationship Between Member Dimension and Weld-induced Stress in Plate-fin Type Heat Exchanger

유동 방향으로 기울어진 사각 핀-휜 열교환기의 유동 및 열전달 특성에 대한 수치적 연구

The flow and heat transfer characteristics of a heat exchanger having rectangular pin-fin in the flow direction have been investigated numerically. On the bottom plate, the convective boundary conditions for the hot side was given, and the fins were arranged in a channel-type geometric model using the periodic boundary condition in the span-wise direction. Three-dimensional numerical calculations for the flow and conjugate heat transfer problem were conducted using SIMPLE algorithm and <TEX>$k-{\varepsilon}$</TEX> turbulence model. For the slanted pin-fin models, it was found that the downward cooling flow is generated due to the downward pressure gradient component, which can enhance the heat transfer performance near the bottom surface and the fin stem region. Four different inclined angles were considered in the Reynolds number range of 13,500-55,000. The aero-thermal performance of the slanted pin-fin heat exchangers, such as the volume and area goodness factors, were summarized and compared with the baseline plate-fin type heat exchanger quantitatively.

Experimental and numerical investigation on the performance of an internally cooled dehumidifier

Liquid desiccant based dehumidifiers are important components of the air conditioning applications. Internally cooled dehumidifiers with liquid desiccants are deemed to be superior to the adiabatic types, thanks to the cooling medium which takes away the latent heat of vaporization occured when moist air contacts with liquid desiccant. However, its utilization in industrial applications is restricted due to the inherent corrosive characteristics of the liquid desiccants. In this study, an experimental chamber is built for epoxy coated plate fin type dehumidifier which is used in order to diminish the corrosive effect of the lithium chloride aqueous solution. Dehumidification effectiveness and moisture removal rate, two parameter indices, are adopted to measure the performance of the air conditioning system. The effect of inlet operating parameters on moisture removal rates is extensively analyzed. Two dimensional numerical model adapted from the conservation principles is utilized for obtainment of output parameters. Experimental results are compared with the numerical model and comparisons show that numerical outputs agrees with the experimental results. And also, dehumidification performance of lithium chloride and lithium bromide aqueous solutions are evaluated and compared against each other.

Study on a Miniature Mixed-gases Joule-Thomson Cooler Driven by an Oil-lubricated Mini-compressor for 120 K Temperature Ranges

In this paper, a miniature J-T cooler using multicomponent mixtures was developed and tested, in which an oil-lubricated mini-compressor was used. Experimental tests on the performance of the miniature J-T cooler were carried out with two kinds of recuperative heat exchangers. One is a shell-and-tube heat exchanger, and the other is a plate-fin type recuperative heat exchanger with whereas a micro-channel configuration fabricated by the wire-electrode cutting method. The former one gave a no-load minimum temperature of 140K, while the later one showsbetter performance. No-load minimum temperature of 110K and about 4W cooling capacity at 118K were achieved with the plate-fin micro J-T cooler. Such miniature J-T coolers driven by oil-lubricated mini-compressors show good prospects in many applications.

Thermal and hydraulic analysis of 3-stream multi fluid (He/He/N2) plate fin heat exchanger for helium plant

One of the key components of helium refrigerator/liquefier (HRL) plant is heat exchangers working at cryogenic temperature. For some cases, heat exchangers with effectiveness less than 90% can be a reason for failure of helium plant to produce liquid helium. To achieve such high effectiveness, it is necessary to use plate fin heat exchangers, which provides very high heat transfer surface area per unit volume. For the heat exchangers of HRL, High effectiveness, compact volume and low pressure drop are main optimizing parameters. The first heat exchanger whose temperature range is ∼310 K to ∼90 K is analysed with plate-fin type heat exchanger. This heat exchanger is a part of indigenous development work of HRL of ∼2 kW cooling capacity at 4.5 K at IPR. Liquid nitrogen (LN2) is used to cool incoming hot He gas around ∼80 K. The detailed thermal and hydraulic analysis is discussed in this paper.