Optimal Heat Dissipation Research Articles

A study on the optimization of cooling performance for oil-immersed transformers in high temperature environments utilizing response surface methodology

To enhance the thermal efficiency of self-cooling oil-immersed transformers in high-temperature environments, this study proposes a method to improve heat transfer by disrupting the boundary layer through incorporating a V-shaped raised structure on the inner wall of the transformer. Numerical calculations using COMSOL software were conducted to compare and analyze the effects of four distinct geometric shapes of protrusions on the thermal performance of 35 kV self-cooling oil-immersed transformers. The results demonstrate that among these four structures, the cone-shaped raised structure exhibits optimal heat dissipation effect and effectively mitigates winding operating temperature. Building upon this finding, response surface methodology was employed for experimental design, constructing a response surface model with minimum winding operating temperature as an objective function while considering variables such as longitudinal spacing (P), height (e), and transverse spacing (g) of cone-shaped protrusions. Through analysis, optimal geometric parameters for cone-shaped raised structures were determined. This research provides an effective solution to address energy consumption and low efficiency issues prevalent in traditional oil-immersed radiators.

Effect of Source-Sink Misalignment and Sink Cavity Aspect Ratio on the Thermal Performance of Gallium Heat Sinks

Herein, we numerically investigated methods to improve heat dissipation from the base of a phase-change material (PCM) heat sink exposed to high heat flux (15 W/cm2). The sink cavity exhibited a rectangular cross-section with two opposite vertical walls of high thermal conductivity. These walls serve as heat-dissipating fins. We used gallium, a metallic PCM with high thermal conductivity and a low melting point to improve heat dissipation by leveraging buoyancy-driven circulations within the molten gallium. We adopted a method to position the sink base on top of the heat source surface in such a way to augment temperature gradients within the liquid to induce imbalances in gallium density and consequent internal circulations. In this technique, one vertical wall is subjected to forced-convective heat exchange with the surroundings, while the other remains adiabatic. Subsequently, for the case which showed optimum performance, we relaxed the adiabatic thermal boundary condition applied at one of the vertical walls and replaced it with convective heat transfer condition, and assessed the sink performance based on that. Further, we analyzed the impact of various aspect ratios of the sink cavity on the induced internal circulations and base cooling. Sink cavities with aspect ratios of 1.33, 0.96, and 0.64 corresponding to sink heights of 20, 17, and 14 mm, respectively, were examined under a consistent heat flux applied across a 15-mm base length. We also investigated the precise positioning of the sink base relative to the heat source surface and explored its influence on temperature gradients and gallium density imbalances crucial for induced internal circulations. Results indicate that a sink cavity aspect ratio of 0.96 yields the optimal heat dissipation from the base. Further, aligning the left bottom edge of the sink base with the left edge of the heat source surface maximizes heat dissipation to the ambient surroundings, thereby prolonging latent-heat dumping into the sink before the gallium completely melts. Any misalignment between the sink base and the surface of the heat source may have a profound impact on the temporal evolution of induced internal circulations within the molten gallium, essentially affecting heat dissipation from the sink base.

Numerical investigation of the influence of heat-generating components on the heat dissipation in a tower server

Many of today’s servers rely on high-power electronic components. During continuous operation, elevated temperatures can lead to sluggish performance and system instability. Therefore, servers urgently require safe and reliable heat dissipation systems. In this work, we focus on a highly scalable tower server as our research subject, exploring its maximum configuration within the designated range. We aim to enhance the server’s thermal performance through a parametric investigation of factors such as the server air outlet, the FAR in air outlet, and the layout of GPUs. The results demonstrate that narrowing the air outlet can effectively reduce the temperature of GPU-2 by 2.83 °C. Further analysis reveals that an optimal FAR of 0.74 for the air outlet leads to a temperature decrease of 1.67 °C for GPU-2 compared to a FAR of 0.24. Moreover, adjusting the position of GPU-2, specifically employing the VLO-L71.16-1 structure with the air outlet positioned on the GPU-1 side, yields optimal heat dissipation performance, resulting in a remarkable temperature decrease of 16.63 °C for GPU-2. Additionally, it was observed that GPU-2 in the base case approaches its limiting temperature. By optimizing the structure to VLO-L71.16-1, the study managed to reduce fan airflow while maintaining GPU-2 within safe operating temperatures. Specifically, the optimal structure achieves approximately 35 % airflow savings when GPU-2 reaches its limiting temperature. This research provides valuable insights for the exploration and design of novel server cooling systems.

Feasibility study on the heat transfer enhancement of gap flow induced by wasted vibration of linear compressor body

Refrigerators account for 20–30 % of household electricity consumption, with the compressor contributing to 80 % of the total consumption. Therefore, it is essential to increase the compressor efficiency. One approach to enhance compressor performance involves increasing heat dissipation to lower the temperature of the suction system and boost the refrigerant density entering the suction chamber. To achieve that innovatively, we harnessed the waste vibration of the linear compressor body to create a gap flow between the body and the housing, enhancing compressor performance by augmenting heat dissipation. Measurements of gap flow temperature, cylinder surface temperature, and heat flux on the cylinder surface were conducted, varying the RPM, gap size, and the shape of the gap flow path. We also observed variations in the gap flow rate with RPM and stroke. The results revealed that gap temperature and heat flux increased with higher RPM and smaller gap size, and the application of ribs to the gap flow path proved to be more effective in enhancing temperature and heat flux. Additionally, it is anticipated that heat flux will further increase with a longer stroke as the flow rate increases. Therefore, to optimize heat dissipation through gap flow using the waste vibration of the compressor body, it is advantageous to employ a smaller gap size, higher RPM, longer stroke, and apply ribs to the gap flow path. Future research should focus on verifying the effectiveness of increased heat dissipation and improved Energy Efficiency Ratio (EER) through actual compressor experiments.

Numerical Study on the Heat Dissipation Performance of Diamond Microchannels under High Heat Flux Density

Heat dissipation significantly limits semiconductor component performance improvement. Thermal management devices are pivotal for electronic chip heat dissipation, with the enhanced thermal conductivity of materials being crucial for their effectiveness. This study focuses on single-crystal diamond, renowned for its exceptional natural thermal conductivity, investigating diamond microchannels using finite element simulations. Initially, a validated mathematical model for microchannel flow heat transfer was established. Subsequently, the heat dissipation performance of typical microchannel materials was analyzed, highlighting the diamond’s impact. This study also explores diamond microchannel topologies under high-power conditions, revealing unmatched advantages in ultra-high heat flux density dissipation. At 800 W/cm2 and inlet flow rates of 0.4–1 m/s, diamond microchannels exhibit lower maximum temperatures compared to pure copper microchannels by 7.0, 7.2, 7.4, and 7.5 °C, respectively. Rectangular cross-section microchannels demonstrate superior heat dissipation, considering diamond processing costs. The exploration of angular structures with varying parameters shows significant temperature reductions with increasing complexity, such as a 2.4 °C drop at i = 4. The analysis of shape parameter ki indicates optimal heat dissipation performance at ki = 1.1. This research offers crucial insights for developing and optimizing diamond microchannel devices under ultra-high-heat-flux-density conditions, guiding future advancements in thermal management technology.

Study on energy-saving techniques of the lithium-ion batteries cooling system using a backup battery

The power battery in an electric vehicle is an essential part, and the damage to the battery will have a substantial impact on its thermal characteristics. In order to improve the reliability of the air-cooled lithium-ion battery packs in the high temperature environments, this paper offers a more useful and general optimization strategy for the design of the thermal management system for the batteries which have a damaged battery. To ensure the optimal heat dissipation and prolong the battery string operation, the damaged batteries should be swapped out with the backup batteries. The relationship between the target and the design variables which was established using the quadratic polynomial response function is examined. The experimental cases are selected using the optimal Latin hypercube design approach. After optimizing through the multi-island genetic approach, the error between the simulation results and the prediction results is only 0.06 %. The maximum temperature and the maximum temperature difference of the ideal structure are reduced by 4.58 % and 28.05 %, respectively. Then, the backup battery is selected as the sole battery that has the highest temperature of the ideal structure, and each broken battery is replaced by the backup battery when the damaged position is determined. Finally, a parametric equation connecting the temperature and the flow rate is created, and the inlet flow rate is tuned to match the optimal heat dissipation state of the battery pack. The results of the battery thermal management system having a damaged battery in various situations have an important significance for adjusting the operating conditions of the cooling system for the batteries.

Quick Prediction of Complex Temperature Fields Using Conditional Generative Adversarial Networks

Abstract Qualified thermal management is an important guarantee for the stable work of electronic devices. However, the increasingly complex cooling structure needs several hours or even longer to simulate, which hinders finding the optimal heat dissipation design in the limited space. Herein, an approach based on conditional generative adversarial network (cGAN) is reported to bridge complex geometry and physical field. The established end-to-end model not only predicted the maximum temperature with high precision but also captured real field details in the generated image. The impact of amount of training data on model prediction performance was discussed, and the performance of the models fine-tuned and trained from scratch was also compared in the case of less training data or using in new electronic devices. Furthermore, the high expansibility of geometrically encoded labels makes this method possible to be used in the heat dissipation analysis of more electronic devices. More importantly, this approach, compared to the grid-based simulation, accelerates the process by several orders of magnitude and saves a large amount of energy, which can vastly improve the efficiency of the thermal management design of electronic devices.

Numerical research on the flow and heat transfer characteristics in the immersion jet cooling for servers

Immersion cooling and jet impingement liquid cooling, as two of the significant emerging direct contact liquid cooling methods, have promising prospects for development and application. The two cooling methods are combined and numerical simulation is applied to study the heat transfer performance of the immersion jet-cooled server. The orthogonal method is employed to determine the optimal structural parameters of the immersion jet, and the flow and heat transfer characteristics under different inlet and outlet layouts are investigated. The study shows that the optimal heat dissipation effect and moderate pressure are achieved when the ratio of jet distance (L) to jet pipe diameter (D) is 1.2, and the ratio of jet hole spacing to jet orifice diameter is 11.1. When the inlet and outlet of the cabinet are arranged in a Z-shaped layout, the pressure on the server surface is reduced by 17.1 %–31.6 % compared to a U-shaped layout. When the inlet and outlet of the cabinet are arranged in a Z-shaped manner with the inlet at the bottom and the outlet at the top, the highest heat transfer coefficient is over 24000 W/(m2· K), which is approximately 1.5 times higher than that of other layouts. Through dimensional analysis, a quadratic function was selected to fit the relationship between heat transfer coefficient h, server pressure P and jet ratio (D/L), opening area A; In addition, the criterion relationship of Nu = f (Re, Eu) is fitted according to the simulation data, which provides a theoretical basis for energy saving and consumption reduction in data centers.

Computational investigation of methanol-based hybrid nanofluid flow over a stretching cylinder with Cattaneo–Christov heat flux

Abstract This study investigates heat transfer rates in (AA7075-AA7072/Methanol) hybrid nanofluid flows, considering non-uniform heat sources and Cattaneo–Christov heat flux, with significant implications for aerospace engineering by enhancing thermal management in aircraft engines. The findings could revolutionize automotive cooling system efficiency, optimize heat dissipation in electronic devices, and advance the design of renewable energy systems such as concentrated solar power plants. The study aims to conduct a comparative analysis of (AA7075/Methanol) nanofluid and (AA7075-AA7072/Methanol) hybrid nanofluid flow, examining heat transfer rates, non-uniform heat sources, and Cattaneo–Christov heat flux theory around a stretching cylinder. Thermal radiation and the Biot number are also evaluated. Two different nanoparticles, AA7072 and AA7075, are used with methanol to create AA7075/Methanol nanofluid and AA7075-AA7072/Methanol hybrid nanofluid. The study compresses the resultant non-linear partial differential equation system and applies suitable similarity transformations to reduce the governing partial differential equations with boundary conditions to dimensionless form. The BVP4C shooting method in MATLAB is employed to numerically and graphically solve these dimensionless ordinary differential equations. The results indicate that higher curvature parameter values correlate with increased velocity and temperature distribution profiles. A rise in nanoparticle volume fraction reduces the radial velocity profile but increases the temperature profile. Temperature distribution profiles increase with higher thermal radiation parameter and Biot number values, while higher thermal relaxation parameter values decrease temperature. Additionally, thermal distribution profiles rise with increasing values of both the time-dependent heat source constant and space-dependent heat source parameter.

A topology optimization-based-novel design and comprehensive thermal analysis of a cylindrical battery liquid cooling plate

In previous studies, the designs of the liquid cooling channel for battery packs usually paid emphasis on optimizing the predefined cooling channels. This significantly restricts the possibilities for geometric modifications of cooling channels, consequently placing limitations on the potential improvement in heat dissipation performance. To address these limitations, this study proposes a Topology optimization-based-novel design and comprehensive thermal analysis of a cylindrical battery liquid cooling plate. The aim of using topology optimization is to overcome these constraints, enabling more flexible and global domain designs. Three different inlet–outlet configurations of the cooling plate structure were designed using a dual-objective optimization function. A comprehensive numerical analysis was conducted and the topology-optimized liquid cooling plate system was compared with two other cooling pipe liquid cooling systems. The effects of coolant flow rate, battery discharge rate, and cooling plate thickness and quantity on the heat dissipation performance of the liquid cooling system were investigated. Findings demonstrate that the topology-optimized cold plate system with four inlets and two outlets exhibits optimal heat dissipation performance. Increases in coolant flow rate, cold plate thickness, and quantity contribute to enhanced cooling performance of the liquid cooling system. Taking into account factors such as pump power consumption, system weight, and heat dissipation performance, a liquid-cooled system with three cold plates and an inlet flow rate of 2.5 × 10-6 m3/s is considered the optimal choice for cooling the battery pack in this study. Under the cooling of this cold plate system, at a coolant and ambient temperature of 25 °C and a discharge rate of 3C, the battery pack’s maximum temperature and temperature difference are 30.9 °C and 4.87 °C, respectively.

Improvement in Laptop Heat Dissipation with Taguchi Method

This paper aims to investigate the feasibility of using system power consumption as a factor to improve laptop heat dissipation. The problems due to the CPU overheating are addressed. Based on the Taguchi method, the laptop fan parameters can be optimized with firmware adjustments only. In the Taguchi analysis, the fan speed, system power, and debounce time are considered as control factors, while the Cinebench point is utilized to evaluate the CPU performance. Experimental results demonstrate that the proposed heat dissipation scheme effectively reduces the idle time of a laptop fan. The improvement in heat dissipation can reduce CPU performance degradation because of overheating. According to the best combination of control factors, there is approximately a 5% increase in CPU performance despite a 0.35% increment in power consumption. This paper highlights the effectiveness of optimizing laptop fan parameters through firmware adjustments to improve heat dissipation and mitigate CPU overheating issues. Moreover, the study highlights the delicate balance between power consumption and performance gains. While there may be a slight increase in power consumption associated with the optimized heat dissipation scheme, the observed improvements in CPU performance outweigh this incremental power usage.

Optimizing BESS performance: Anisotropic thermal properties and innovative parallel-flow cooling solutions

As the demand for efficient energy storage solutions intensifies, container-type battery energy storage systems (BESS) have gained prominence. BESS usually utilizes large-format laminated lithium-ion battery (LIB) modules, which inherently possess unique anisotropic thermal properties. Specifically, the surface regions with elevated temperatures exhibit high thermal conductivity, while the cooler zones at both ends manifest reduced conductivity. Such disparities emphasize the challenge of developing an effective battery thermal management system (BTMS) for these modules. To address this, our study introduces an innovative BTMS configuration wherein the batteries are aligned in series, while cooling air flows parallel to them. This parallel-flow cooling approach capitalizes on the anisotropic properties, intensifying airflow over the surfaces and recirculating cooling air to optimize heat dissipation from hotspots. Consequently, our system reduces the peak temperature from 42.3 °C to 37.5 °C, as well as the temperature difference (ΔT) from 14.3 °C to 10.2 °C across the entire BESS, respectively representing 11.3 % and 28.7 % changes. This leads to a substantial 75.9 % enhancement in the performance index, significantly augmenting both the safety and commercial viability of the BESS.

Thermal profiling of ultracapacitor modules : A layered analysis

This study explores heat dissipation in supercapacitor modules tailored for energy-intensive applications. The research investigates the influence of different electrode material combinations on key performance parameters. Employing MATLAB and COMSOL simulations, the thermal conductivity of various layers within the supercapacitor module is analyzed. Findings reveal that polythene separators, responsible for encapsulating and segregating the module’s electrodes, represent critical points for controlled heat transfer. Significantly, the use of metal oxide in electrode construction contributes positively to regulated heat dissipation. Substituting polythene separators with synthesized materials is proposed to optimize heat dissipation. This research pioneers a data-driven analysis and software simulations to augment the study’s outcomes.

Thermal Optimization Design of a Intelligent Programmable Controller Based on CFD Software

With the increasing functionality of intelligent programmable controllers and the continuous improvement in power and component density, the problem of rapidly rising temperatures during operation has become increasingly prominent, directly affecting the controller's lifespan and stability[1]. Therefore, improving the heat dissipation efficiency of intelligent programmable controller modules has become a key focus of research. This paper introduces a method of installing aluminum alloy heat sinks on the core chip of the controller and carefully designing the fin shape and size of the heat sink to enhance heat conduction and heat convection effects, improving heat dissipation performance. This paper also constructs a thermal equivalent model of the controller and simulates the impact of different fin parameters on heat dissipation performance. Experimental results show that when the fin height is 5 millimeters, thickness is 2 millimeters, and spacing is 4 millimeters, the heat sink exhibits the highest thermal conductivity and the lowest thermal resistance, achieving optimal heat dissipation effectiveness.

Maximizing electrical output and reducing heat-related losses in photovoltaic thermal systems with a thorough examination of flow channel integration and nanofluid cooling

In recent years, global energy demand has surged, emphasizing the need for nations to enhance energy resources. The photovoltaic thermal (PV/T) system, capable of generating electrical energy from sunlight, is a promising renewable energy solution. However, it faces the challenge of overheating, which reduces efficiency. To address this, we introduce a flow channel within the PV/T system, allowing coolant circulation to improve electrical efficiency. Within this study, we explore into the workings of a PV/T system configuration, featuring a polycrystalline silicon panel atop a copper absorber panel. This innovative setup incorporates a rectangular flow channel, enhanced with a centrally positioned rotating circular cylinder, designed to augment flow velocity. This arrangement presents a forced convection scenario, where heat transfer primarily occurs through conduction in the uppermost two layers, while the flow channel beneath experiences forced convection. To capture this complex phenomenon, we accurately address the two-dimensional Navier–Stokes and energy equations, employing simulations conducted via COMSOL 6.0 software, renowned for its utilization of the finite element method. To optimize heat dissipation and efficiency, we introduce a hybrid nanofluid comprised of titanium oxide and silver nanoparticles dispersed in water, circulating through the flow channel. Various critical parameters come under scrutiny, including the Reynolds number, explored across the range of 100–1000, the volume fractions of both nanoparticle types, systematically tested within the range of 0.001–0.05, and the controlled speed of the circular cylinder, maintained within the range of 0.1–0.25 m/s. It was found that incorporating silver nanoparticles as a suspended component is more effective in enhancing PV/T efficiency than the addition of titanium oxide. Additionally, maintaining the volume fraction of titanium oxide between 4 and 5% yields improved efficiency, provided that the cylinder rotates at a higher speed. It was observed that cell efficiency can be regulated by adjusting four parameters, such as the Reynolds number, cylinder rotation speed, and the volume fraction of both nanoparticles.

Liquid crystal elastomer film actuators with anti-strain robustness

Thermotropic monodomain liquid crystal elastomers (mLCEs) exhibit reversible contractile actuation properties along the collimated direction of mesogens when stimulated by external temperature, similar to those of biological skeletal muscle, and have great potential applications in flexible actuators and artificial muscles. However, the existence of flexible chain segments causes mLCEs to elongate under a small load, making calibration under different loads necessary when they are used as an actuator. In this study, a physical crosslinking point between flexible segments is provided through the introduction of designed long-chain molecules (LHS) containing amide bonds on the main chain of LCEs. The 5% LHS-mLCEs with enhanced anti-strain robustness achieved essentially constant original length over a range of loads (0–0.25 MPa) and maintained a reversible contraction ratio of 39.4%, comparable to biological skeletal muscle. Furthermore, a nonreconfigurable topological structure of a metal electrothermal layer with lossless compression properties was designed and prepared on the surface of mLCEs. The film actuators exhibit higher frequency oscillatory actuation (0.1 Hz 9.2%; 0.2 Hz 6.3%; 0.5 Hz 2%) relative to previously reported actuators, benefitting from the optimized heat dissipation structure of LCEs/Ag/air. This study provides valuable references and ideas for applying thermotropic mLCEs in practice.

A Simulation of Thermal Management Using a Diamond Substrate with Nanostructures.

In recent years, the rapid progress in the field of GaN-based power devices has led to a smaller chip size and increased power usage. However, this has given rise to increasing heat aggregation, which affects the reliability and stability of these devices. To address this issue, diamond substrates with nanostructures were designed and investigated in this paper. The simulation results confirmed the enhanced performance of the device with diamond nanostructures, and the fabrication of a diamond substrate with nanostructures is demonstrated herein. The diamond substrate with square nanopillars 2000 nm in height exhibited optimal heat dissipation performance. Nanostructures can effectively decrease heat accumulation, resulting in a reduction in temperature from 121 °C to 114 °C. Overall, the simulation and experimental results in this work may provide guidelines and help in the development of the advanced thermal management of GaN devices using diamond micro/nanostructured substrates.

The Arrangement and Cross-sectional Shape of Cooling Fins on Train Brake Discs

Taking into account physical factors such as the wind effect of the brake disc pump, heat dissipation power, and temperature rise, the optimal cross-sectional shape and layout of the brake disc cooling fins are studied. The flow field distribution and pump-wind heat dissipation power ratio of four different cross-sectional shapes, namely circular, elliptical, square, and rhombic, are compared and analyzed. The flow characteristics, wind effect, and heat dissipation power of the cooling fins under two different layouts, namely crosswise and parallel layouts, are also analyzed. The research results show that the circular cooling fins have the optimal pump-wind loss and heat dissipation power, and the crosswise layout of cooling fins shows the best comprehensive performance. The performance analysis method of cooling fins obtained in this paper provides a reference for the optimization design of brake disc structures.

Parameter optimization and sensitivity analysis of a Lithium-ion battery thermal management system integrated with composite phase change material

In order to ensure the performance and to extend the life cycle of power battery module within electric vehicle, a battery thermal management system (BTMS) integrated with composite phase change materials (PCM) was proposed. The heat dissipation performance of BTMS using paraffin/expanded graphite (EG) composite PCM with different mass fraction was investigated. The results showed the optimal heat dissipation performance was observed using composite PCM with 20 wt% EG. The combined effect of liquid volume fraction and thermophysical parameters of composite PCM on heat dissipation performance of battery module was revealed. The phase transition temperature of composite PCM was found to have the largest impact on the maximum temperature and temperature uniformity of battery module, followed by latent heat and thermal conductivity of composite PCM. A 10 % decrease in the phase transition temperature led to a 7.9 % in the maximum temperature of battery module. Both the thermal conductivity and latent heat growth contributed to the reduction in the maximum temperature of battery module. Composite PCM with the thermal conductivity of 3 W m−1 K−1, phase change temperature of 38 °C, and latent heat of 220 J g−1, was found to achieve the optimal heat dissipation performance of BTMS and a high utilization rate of 97.3 % for composite PCM. The findings of this work could be beneficial for future development of highly-efficient and economical composite PCM for BTMS.

Placement and size-oriented heat dissipation optimization for antenna module in space solar power satellite based on interval dimension-wise method

Space solar power satellite is one of the large space systems for supplying solar energy in the future, and its effective thermal management and heat dissipation can affect safety and efficiency. To balance the mass and temperature distribution in the antenna module, a novel placement and size-oriented heat dissipation optimization is proposed in space solar power satellite based on an interval dimension-wise method considering both design and uncertain variables. To improve the accuracy of the interval propagation, a novel interval dimension-wise method is investigated based on the Legendre polynomial approximation model and the union operator of the boundary points combinations. A novel mapping matrix with sensitivity analysis is developed to determine the final design variables from the candidate ones, which constitutes a relationship between the uncertain parameters and design variables. The placement and size-oriented heat dissipation optimization is solved using the coevolutionary constrained multi-objective optimization framework (CCMO), and thermophysical response intervals of optimal heat dissipation layout can be obtained using the interval dimension-wise method again. The effectiveness of the proposed method is verified by two numerical examples, which can reflect the applicability of the proposed heat dissipation.