Parallel Plate Fin Research Articles

Design Modeling and CFD Simulation of Parallel Plate–Fin Heat Sink Under Natural Convection

The lifetime of electronic devices strongly depends on the junction temperature. Heat sinks are a good choice for dissipating heat because of their enhanced heat transfer areas. Plate–fin heat sinks are commonly used for electronic components because of their simple construction. Recently, computational fluid dynamics (CFD) software, such as Ansys Fluent and OpenFOAM, has been widely used and has provided effective results. Autodesk CFD is a powerful simulation tool; however, its use in heat sink research remains relatively uncommon. In this study, two plate–fin heat sinks with heights of 30 and 50 mm were first designed using heat transfer equations and then compared with Autodesk CFD simulations under natural convection conditions. Temperature inputs of 60 °C, 70 °C, and 80 °C were assigned to determine the temperature distribution along the fins, heat dissipation, fin efficiency, and fin effectiveness for both types of heat sinks. The results of the heat transfer calculations and Autodesk CFD simulations are consistent, with negligible differences. These findings indicate that Autodesk CFD can produce reliable results for heat sink design. In addition, efficiency decreases with the increase in fin height, although the effectiveness and heat dissipation of the tall (50 mm) heat sink are higher than those of the short (30 mm) heat sink. Although the 50-mm-high fin heat sink has a heat transfer area approximately 63% larger than that of the 30-mm-high fin heat sink, its heat dissipation is only approximately 40% larger than that of the 30-mm-high fin heat sink. This finding indicates that the addition of more material alone may not proportionally increase heat transfer and could lead to wasted material. Therefore, when designing heat sinks, the height of the fins should be carefully considered and optimized to enhance efficiency and conserve materials.

NUMERICAL INVESTIGATIONS OF THERMO-FLUIDIC CHARACTERISTICS IN INNOVATIVE PARALLEL PLATE-FIN HEAT SINK DESIGN SUBJECTED TO PARALLEL FLOW: EXPLORING THE STAGGERING EFFECT

NUMERICAL INVESTIGATIONS OF THERMO-FLUIDIC CHARACTERISTICS IN INNOVATIVE PARALLEL PLATE-FIN HEAT SINK DESIGN SUBJECTED TO PARALLEL FLOW: EXPLORING THE STAGGERING EFFECT

Performance of parallel plate-fin heat exchanger for piston aero-engines with front-placed guide plate at high altitude

• Heat exchangers’ performance in aircraft is enhanced by installing guide plates. • New indicators relating thermal performance to structural parameters are proposed. • The effect of inclination angle on thermodynamic performance is discussed. • The shielding proportion would significantly affect the heat transfer capacity. • Correlations are obtained to predict high-altitude characteristics. The reduction in atmospheric density would hinder the normal operation of the cooling system of piston aero-engines, thus influencing the aircraft’s performance in all aspects. This paper first introduced a composite structure consisting of a plate-fin heat exchanger and a front-placed guide plate to strengthen the heat transfer capacity. The improvement was evaluated and predicted by CFD (computational fluid dynamics) simulations at different altitudes. The optimal layout parameters of the guide plate, such as the inclination angle and the shielding proportion, were also explored. To scientifically elucidate the relationship between heat dissipation, flow performance, and structure parameters, the conception of effective mass rate was proposed for the first time. The results showed that the enhancement of the composite structure in heat transfer rate achieved a maximum improvement rate of 34.9% at 20 km altitude. Also, different arrangements of the guide plate directly affected the thermal and flow performance. Below 11 km, the best inclination angle of the plate was 30°, while above 11 km, it became 45°. The optimal gap in partial shielding cases decreased within 7∼9 mm as the altitude increased. Finally, relevant correlations for predicting the flow and heat transfer characteristics of the heat exchanger at different altitudes were developed in this study.

DESIGN OPTIMIZATION OF A POWER MODULE BOX IN 3D RADAR SYSTEM

This paper researches a design process of a heatsink in the power module box of the 3D Radar system. Studying the theory of heat transfer across parallel plate-fins of the heatsink to optimize the geometric parameters. The power module boxes are designed based on those optimum geometric parameters. In the next step, the design model is used to simulate temperature under working conditions by using Solidworks simulation software. The design model is then trial manufactured for testing before moving to the mass production.

Heat Exchanger Assisted Exhaust Heat Recovery with Thermoelectric Generator in Heavy Vehicles

The automobile industry is in a constant pursuit to improve the fuel economy of vehicles. The internal combustion engine is inefficient due to its inherent irreversibility. Around 30% of the combustion energy is lost in the form of heat with the exhaust gasses. If this lost energy is recovered and utilized, then it will improve the overall fuel economy of the vehicle. Herein, a waste heat recovery concept is presented to recover heat from exhaust gasses in a heavy commercial vehicle. Two exhaust gas heat exchangers are conceptualized and their performances are compared. A novel idea of immersing thermoelectric modules in coolant is proposed instead of using a separate cooling block or channel. The thermal performance is evaluated considering transformer oil as coolant instead of commonly used engine coolant. The performance of two heat exchangers one having a parallel flat plate fin core and the other having a pin fin core configuration is investigated. The effect of coolant volume flow rate and exhaust gas mass flow rate also is analyzed.

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.

Optimization of geometric design parameters for a parallel plate fins heatsink of broadcast vehicle system

This paper researches a design process of a parallel plate-fins heatsink subjected to an impinging airflow in a broadcast vehicle system. First, it is demonstrated theoretically that the thermal conductance between the plate and the air stream can be maximized by optimizing geometric parameters. Next, the research studies the heat transfer theory across parallel plate-fins of the heatsink to optimize the geometric parameters. Those parameters are used to design a three-dimensional heatsink. In the next step, the design model simulates temperature under working conditions by using computational fluid dynamics (CFD). The simulation results show that the maximum temperature is smaller than the maximum permitted temperature of electronic equipment given by the manufacturer. Then, the design model is trial manufactured for testing before moving to mass production.

3D topology optimization of heat sinks for liquid cooling

Abstract This paper conducts topology optimization of three dimensional heat sinks for liquid cooling. The forced cooling system is modeled with weakly coupled steady-state incompressible Navier-Stokes equation and the energy equation. We study the distribution of the conductive solid components in order to minimize the average temperature on the heat source surface. A set of consistent adjoint equations are derived from the weak forms of the state equations in order to obtain the sensitivity. We discretize the simulation domain with six million tetrahedral elements. Iterative solvers with preconditioners are used to solve the partial differential equations. We present three examples with different geometries and boundary conditions as benchmarks for topology optimization of forced cooling problems. Detailed numerical validations on one design from topology optimization show that the optimized parallel plate fin heat sink could consume up to 450% more pumping power than the topology optimization design while achieving the same thermal performance, or the temperature of the optimized parallel plate fin heat sink is 10–40% higher than the design from topology optimization when the pumping power is same. The superior performance of the design from topology optimization is achieved with a flow split effect due to the heat sink geometry. This geometry sends the hot flow to the top layer and the cold flow to the bottom layer further in the downstream region in an aerodynamically efficient manner.

Comparing exergy losses and evaluating the potential of catalyst-filled plate-fin and spiral-wound heat exchangers in a large-scale Claude hydrogen liquefaction process

Abstract Detailed heat exchanger designs are determined by matching intermediate temperatures in a large-scale Claude refrigeration process for liquefaction of hydrogen with a capacity of 125 tons/day. A comparison is made of catalyst filled plate-fin and spiral-wound heat exchangers by use of a flexible and robust modeling framework for multi-stream heat exchangers that incorporates conversion of ortho-to para-hydrogen in the hydrogen feed stream, accurate thermophysical models and a distributed resolution of all streams and wall temperatures. Maps of the local exergy destruction in the heat exchangers are presented, which enable the identification of several avenues to improve their performances. The heat exchanger duties vary between 1 and 31 MW and their second law energy efficiencies vary between 72.3% and 96.6%. Due to geometrical constraints imposed by the heat exchanger manufacturers, it is necessary to employ between one to four parallel plate-fin heat exchanger modules, while it is possible to use single modules in series for the spiral-wound heat exchangers. Due to the lower surface density and heat transfer coefficients in the spiral-wound heat exchangers, their weights are 2–14 times higher than those of the plate-fin heat exchangers. In the first heat exchanger, hydrogen feed gas is cooled from ambient temperature to about 120 K by use of a single mixed refrigerant cycle. Here, most of the exergy destruction occurs when the high-pressure mixed refrigerant enters the single-phase regime. A dual mixed refrigerant or a cascade process holds the potential to remove a large part of this exergy destruction and improve the efficiency. In many of the heat exchangers, uneven local exergy destruction reveals a potential for further optimization of geometrical parameters, in combination with process parameters and constraints. The framework presented makes it possible to compare different sources of exergy destruction on equal terms and enables a qualified specification on the maximum allowed pressure drops in the streams. The mole fraction of para-hydrogen is significantly closer to the equilibrium composition through the entire process for the spiral-wound heat exchangers due to the longer residence time. This reduces the exergy destruction from the conversion of ortho-hydrogen and results in a higher outlet mole fraction of para-hydrogen from the process. Because of the higher surface densities of the plate-fin heat exchangers, they are the preferred technology for hydrogen liquefaction, unless a higher conversion to heat exchange ratio is desired.

Performance of a guided plate heat sink at high altitude

Abstract In the present study, the thermal performance of an enhanced air-cooled heat sink system, comprising of a parallel plate-fin heat sink (PPFHS) with a guide plate installed to alter the bypass flow, was analyzed for fan-driven convection conditions at various altitudes from sea level to 12,000 m. Numerical simulations were carried out using ANSYS Fluent 16.0 with the κ - ω SST turbulence model to analyze the airflow and assess the thermal performance. After validation by experimental data in the literature, numerical results of the flow and temperature fields were obtained for different environmental pressures, several fan speeds and PPFHS design parameters. The measured characteristic fan curves at different altitudes show that the fan delivers approximately the same volume flow rate at different altitudes. For high-altitude operation, using the PPFHS only configuration could lead to electronic failure due to the larger temperature increase compared to using the PPFHS/guide plate configuration. For both configurations, the optimum fin number ranges between 20 and 32, which depends on the environmental pressure and fan speed. Improper use of highly dense PPFHS may lead to inadequate electronic cooling and will add extra weight for high-altitude operation. The optimal fin thickness depends on the fan speed, and the minimum thermal resistance occurs with low fin thickness at the lower fan speeds. Weight optimization procedures were conducted to obtain a considerable decrease in the PPFHS/guide plate weight and to achieve optimal thermal resistance at lower fan speeds.

A general distributed-parameter model for thermal performance of cold box with parallel plate-fin heat exchangers based on graph theory

For predicting the thermal performance of cold box with parallel plate-fin heat exchangers, a general distributed-parameter model based on graph theory was developed. In the present study, a mathematical description model of cold box based on graph theory was established, capable of describing the connection relations of multiple streams and components in cold box; a distributed-parameter thermal performance model of plate-fin heat exchangers based on approximate analytical method was developed, and the temperature gradients along both axial and transversal directions are reflected; a mass flow rate distribution model of parallel pipelines based on the pressure balance was presented to calculate the flow distribution of multiple streams in pipelines. A tailor-made iteration algorithm using graph-based traversal method was developed to solve the present model. The validation of the proposed model shows that the deviations of the calculated heat capacity and outlet temperature of natural gas from experimental data are −1.9% and +4.35 °C, respectively.

Heat transfer enhancement of inclined projected winglet pair vortex generators with protrusions

Abstract Heat transfer enhancement in parallel plate-fin heat exchanger is examined by performing three-dimensional numerical simulations of longitudinal vortex generators (VG) with protrusions. The turbulence is modeled using the shear-stress transport (SST) κ-ω model and validated with correlations and experimental data at Reynolds number equal to 4600. Hemi-spherical protrusions are inserted downstream two VG configurations: delta winglet type (DWP) and a new VG configuration named inclined projected winglet pair (IPWP), in various locations, leading to the definition of six different configurations. Based on the streamwise distribution of Nusselt number and friction coefficient criteria in addition to vorticity, the local performance is analyzed. Some VGs with protrusions are examined and show better performance relative to VGs standing alone. The present study highlights the different mechanisms involved in the convective heat transfer intensification by generating multiple interacting vortices while adding protrusions with low pressure drop penalty. Finally, it is found that the IPWP with protrusions, set downstream in the middle, bestows the best global performance with about 7.1% heat transfer enhancement compared to DWP configuration.

Analysis and Modeling of Thermal Effect and Optical Characteristic of LED Systems With Parallel Plate-Fin Heatsink

Based on the photoelectrothermal (PET) theory, prediction methods for the thermal effect and optical properties of the light-emitting diode (LED) systems mounted on a given parallel plate-fin heatsink are proposed in this paper. With the PET theory and the heatsink characteristics (heat transfer coefficient, equivalent radius for heat source, fins efficiency), it is possible to accurately quantify junction temperature, heat dissipation coefficient, optical power, and luminous flux of the LED systems. The prediction model consists of a series of optical and thermal evaluation, with which it is simple for LED system designers to comply. The proposed model has been validated using LED sources, which shows good agreement between the calculated and experimental results.

A mathematical model for flow maldistribution study in a parallel plate-fin heat exchanger

Abstract In this paper, a mathematical model is developed to quantitatively evaluate the effect of flow maldistribution in a multi-channel heat exchanger. A computational fluid dynamics (CFD) technology is used to obtain the fluid distribution in the core of heat exchanger, taking into account the effects of gross passages, headers and distributors, etc. Based on the CFD simulation profile, a heat exchanger model is then developed. A parallel plate-fin heat exchanger with N flow passages is divided into N sub-exchangers when only one fluid is in maldistribution mode or 2N-1 sub-exchangers when both fluids are in nonuniformity modes to guarantee the uniform flow patterns in each sub-exchanger. Based on e-NTU theory, the effectiveness of the heat exchanger is calculated by modeling the heat exchanger as a parallel coupling of the sub-exchangers. The core pressure drop of the whole heat exchanger is taken as the average pressure drop of the sub-exchangers. The mathematical model combining with the achieved flow distribution was utilized to investigate the performance of the heat exchanger with conventional header configurations, a punched baffle header configuration and a quasi-S header configuration, respectively. Results indicated that a good synergy of flow rates for both cold and hot fluids in the adjacent sub-exchangers can effectively reduce effectiveness deterioration. The performance of the heat exchanger is improved by using the improved header configurations. And the performance with a quasi-S header configuration is the best. The proposed mathematical model provides a theoretical basis for multi-channel heat exchangers in solving the problem of flow maldistribution.

Novel design of delta winglet pair vortex generator for heat transfer enhancement

Heat transfer is a naturally occurring phenomenon that can be greatly enhanced with the aid of vortex generators (VG). Three-dimensional numerical simulations of longitudinal vortex generators are performed to analyze heat transfer enhancement in parallel plate-fin heat exchanger. The shear-stress transport (SST) κ-ω model is adopted to model the flow turbulence. Empirical correlations from the open literature are used to validate empty channel simulations. First, numerical simulations are conducted for the classical delta winglet pair (DWP) which is introduced as the reference case in this study. Then, an innovative VG configuration, named inclined projected winglet pair (IPWP), is examined and it shows superior performance relative to the DWP. The IPWP exhibits similar heat transfer rates than that of the DWP but with lower pressure drop penalty due to its special aerodynamic design. The local performance is analyzed based on the streamwise distribution of Nusselt number and friction coefficient criteria in addition to vorticity. This study highlights the different mechanisms involved in the convective heat transfer intensification by generating more vortices using more aerodynamic VG shape while decreasing the pressure drop penalty.

Experimental Study of Air-Cooled Parallel Plate Fin Heat Sinks with and without Circular Pin Fins between the Plate Fins

Experiments were conducted to investigate forced convective cooling performance of an air cooled parallel plate fin heat sink with and without circular pin fins between the plate fins. The original parallel plate heat sink was fabricated consist of 9 parallel plates of length 53 mm with cross-sectional area of 1.4 mm in width by 20 mm height for each plate. The second heat sink has the same geometry of original one but with some circular pins between the plate fins. Thermal and hydrodynamics performances of the heat sinks have been assessed from the results obtained for the pressure drop, thermal resistance and overall performance with the free stream air velocity ranging from 4.7 to 12.5 m/s. Results show that the free stream air velocity has a significant effect on the thermal and hydrodynamics performance of the system. With increasing free stream velocity, the heat transfer coefficient increases and consequently the thermal resistance decreases while pressure drop increases due to higher inertial of fluid at higher velocities. Furthermore, at the same free stream air velocity the thermal resistance for the heat sink with circular pin is about 37.7% lower than that of the original heat sink.

Enhancement of Natural Convection Heat Transfer within Closed Enclosure Using Parallel Fins

A numerical study of natural convection heat transfer in water filled cavity has been examined in 3-Dfor single phase liquid cooling system by using an array of parallel plate fins mounted to one wall of a cavity. The heat generated by a heat source represents a computer CPU with dimensions of 37.5∗37.5mm mounted on substrate. A cold plate is used as a heat sink installed on the opposite vertical end of the enclosure. The air flow inside the computer case is created by an exhaust fan. A turbulent air flow is assumed and k-e model is applied. The fins are installed on the substrate to enhance the heat transfer. The applied power energy range used is between 15 - 40W. In order to determine the thermal behaviour of the cooling system, the effect of the heat input and the number of the parallel plate fins are investigated. The results illustrate that as the fin number increases the maximum heat source temperature decreases. However, when the fin number increases to critical value the temperature start to increase due to the fins are too closely spaced and that cause the obstruction of water flow. The introduction of parallel plate fins reduces the maximum heat source temperature by 10% compared to the case without fins. The cooling system maintains the maximum chip temperature at 64.68°C when the heat input was at 40W that is much lower than the recommended computer chips limit temperature of no more than 85°C and hence the performance of the CPU is enhanced.

Analytical Study on Multi-stream Heat Exchanger Include Longitudinal Heat Conduction and Parasitic Heat Loads

Abstract High performance heat exchangers are critical component in many cryogenic systems and its performance is typically very sensitive to longitudinal heat conduction, parasitic heat loads and property variations. This paper gives an analytical study on 1-D model for multi-stream parallel-plate fin heat exchanger by using the method of decoupling transformations. The results obtained in the present paper are valuable for the reference on optimization for heat exchanger design.

自然对流下LED集成芯片整体式热管散热器性能实验研究

In order to solve the problem of cooling LED multi-chip LED module,an integrated heat pipe heat sink was designed and fabricated. Heat dissipation experiments were conducted to study effects on heat load,filling ratio and inclination angle on the thermal performance of the heat sink in nature convection. The results show that the efficient heat transfer of the heat pipe can reduce the thermal resistance of the heat sink effectively and the optimum filling ratio is 30% in this research.Inclination angle in the range of 0°- 50° has little effect on heat transfer capability of heat pipe at lower heat load. When the angle reaches 75°,heat transfer of heat pipe and thermal resistance of heat sink are all subject to a significant deterioration. The time heat sink enters stable state is about30 min and is not affected by the magnitude of the power. However,the heat sink works stably after40 min when angle is 75°. Compared to traditional parallel plate fins and sunflower fins heat sink,the chip junction temperature with integrated heat pipe heat sink is smallest.

Fouling and pressure drop analysis of milk powder deposition on the front of parallel fins

One method to reduce the energy consumption of industrial milk spray dryers is to recover waste heat from the exhaust dryer air. A significant challenge associated with this opportunity is the air contains a small amount of powder that may deposit on the face and surfaces of a recuperator. This paper introduces a novel lab based test that simulates powder deposition on a bank of parallel plate fins at exhaust dryer air conditions. The fin bank acts like the face of a typical finned tube row in a recuperator. The aim of this study is to look at how deposition on the front of fins is affected by the air conditions. Results show similar characteristics to other milk powder deposition studies that exhibit a dramatic increase in deposition once critical stickiness levels are reached. As powder deposits on the face of the fins, the pressure drop across the bank increases until eventually an asymptote occurs, at which point the rates of deposition and removal are similar. For very sticky conditions, deposition on the face of the fins can cause a rise in the pressure drop by as much as 65%. The pressure drop has also been successfully related to the percentage of open frontal area of the fins with and without deposition. Deposition inside and at the rear of the fin bank was found to be minimal.