Actual stresses around TSV in whole 3D-SiP under reflow or power ON/OFF thermal load

Numerical study on the heat transfer performance of non-Newtonian fluid flow in a manifold microchannel heat sink

Effect of gas-liquid two-phase macro-mixing on the uniformity of temperature distribution in a top-blown stirred tank using image analysis

Hardening is widely used in production of various workpieces like balls for ball bearings. Processes of spheres heat treatment are in attention focus because of mass production. High requirements to profitability, accuracy, and repeatability are imposed to these processes. Classical technologies of gas and electric heating do not meet these requirements because intensities of heating are small and therefore internal parts of spheres become also warm. So, induction heating misplaces traditional heating technologies in this process. Typical designs of inductors are unsuitable as they do not provide the required uniformity of heating for hardening. However, technologies of induction heating need to be adapted for heat treatment of spherical workpieces. In this article a new design of the inductor for spheres hardening is proposed. It allows obtaining uniform distribution of temperature on the surface of heated sphere. To investigate the proposed design, the numerical model of installation has been developed in the Cedrat FLUX v 10.4 software package. The uniform temperature distribution on a sphere surface is obtained. Temperature difference on the surface of the sphere is 30°C which meets requirements to the hardening process. The internal part of sphere is not heated up because of the high speed of heating in the inductor. It allows increasing heating efficiency as there is no energy consumption for heating within sphere's core Also, the combination of high skin hardness and the viscoelastic middle is reached. It raises durability of the ball bearing and its reliability. The aim of the article is to show the approach to geometrical design of inductor to achieve uniform surface temperature distribution for the heated ball. Numerical modeling is carried out for the analysis of the design proposed.

Glycerol-assisted co-electrolysis in solid oxide electrolyzer cell (SOEC) for green syngas production: A 2D modelling study

Thermodynamic performance and flow structures analysis of supercritical CO2 applied in a regenerative cooling channel mounted with mini-ribs

Interstitial arrays of insulated antennas have shown promise for microwave hyperthermia treatment of deep-seated tumors. Available analytical techniques for predicting the electromagnetic (EM) power deposition of these antennas have been limited to the case of a homogeneous conductive medium surrounding the array. Since tumors and host tissue may differ in their electrical characteristics, it is necessary to consider the impact of this variation in electrical properties and the geometry of the tumor in the calculation of the EM field distribution and power deposition pattern when modeling interstitial antennas. In this paper a three-dimensional model of a tumor of arbitrary shape subjected to the fields of an interstitial antenna array is developed to predict the EM power deposition in an inhomogeneous tumor-tissue medium. The volume integral equation for the imbedded tumor is developed and solved by method of moments. The incident fields are calculated based on the available formulation of interstitial antennas in homogeneous media. The accuracy of the developed computer code was checked by comparing the results from the volume integral approach with the Mie solution for the special case of spherical tumors. Good comparison was obtained for tumors with properties approximately 25 percent different from those of the surrounding tissue. Comparisons of results from models of antenna arrays with and without imbedded tumors show significant differences in their predictions of the EM power deposition in the tumor. Hyperthermia protocols generally specify uniform temperature distribution within the tumor. The developed inhomogeneous model was used to examine the feasibility of controlling the uniformity of the power deposition pattern in large tumors by adjusting the amplitude or relative phase between the array elements. Results are presented to show that a phase lead of +90 degrees or relative amplitude of 4.0 on one antenna in a square array of four antennas could be used to shift the power deposition pattern to sequentially heat outer portions of a 2 cm diameter tumor, thereby achieving a more uniform time-averaged temperature distribution in the tumor.

The continuous increase in power density of electronic devices imposes stringent requirements on the design of lightweight, high-efficiency heat sinks. To overcome the limitations of conventional single-gradient or monomaterial heat sinks—namely, their suboptimal heat-transfer efficiency and poor structural adaptability—this study proposes a dual-gradient, triply periodic minimal surface (TPMS)-based multimaterial heat sink architecture fabricated from CuCrZr and AlSi7Mg. Thermal performance was quantified experimentally using infrared thermography, while the underlying flow-field mechanisms were investigated numerically via computational fluid dynamics (CFD) simulations employing the standard k–ε turbulence model. With the TPMS material volume ratio fixed at 3:3 (CuCrZr:AlSi7Mg), the Z-axis gradient configuration P-Z4-5 delivered the best overall thermal performance, achieving a heat-transfer coefficient (HTC) of 1557.63 W·m−2·K−1 and a thermal resistance as low as 1.83 K·W−1 at an inlet velocity of 5 m·s−1. In contrast, the Y-axis gradient configuration P-Y3-6 yielded the most uniform temperature distribution, exhibiting a maximum surface temperature difference of only 21.5 °C under the same inlet condition. Velocity and turbulence distribution analyses reveal that the dual-gradient design enhances both the narrow-tube effect and flow-induced disturbances; furthermore, increasing the inlet velocity from 5 m·s−1 to 21.65 m·s−1 significantly intensifies vorticity-driven fluid mixing. Among all configurations evaluated, P-Z4-5 exhibited the highest j/f factor (i.e., the ratio of Colburn j-factor to Fanning friction factor), followed by P-Z3.5-5.5 and P-Z3-6. These findings establish a promising new pathway for the development of high-performance, lightweight heat sinks tailored for next-generation high-power electronics.

The performance and life cycle of Li-ion batteries are governed by the maximum temperature and uniformity of temperature distribution in the battery pack, and an efficient thermal management system is highly desired to keep the operating temperature of the battery pack within safe operating limits. Air cooling has received extensive attention in the area of battery thermal management. However, performance intensification of air-cooling modules is essential while keeping the simplicity of design to satisfy the weight and space constraints of electric vehicle (EV) applications. In the current work, efforts have been made to design a simple and generalized air-cooling module for efficient thermal management of Li-ion batteries. The current work explored the effect of two common air flow configurations: side inlet and side outlet (SS) and side inlet and front outlet (SF), with different number of inlet/outlet ports (single inlet and single outlet, single inlet and two outlets, two inlets and single outlet, and two inlets and two outlets) on the thermal and hydraulic performance of Li-ion battery pack. Subsequently, a new design of battery module with an open outlet port is proposed. It is observed that the way fluid leaves the cooling module significantly influences the flow and temperature distribution uniformity of the battery pack. Significant improvement in the fluid flow distribution and lower temperature fluctuation are maintained by the SF designs as compared to the SS designs. Among all SS designs, only SS-Ib at Vin ≥ 5.6 m/s and SS-IV at Vin ≥ 4.8 m/s are found suitable for the thermal management of Li-ion battery pack, whereas all SF designs maintained desired Tmax and ΔTmax conditions at Vin ≥ 4.8 m/s. Furthermore, the new design (SF-V) with an open outlet results in the reduction of Tmax by 7 °C and ΔTmax by 64.5% as compared to base design (SS-Ia) at the same pressure drop penalty.

High speed and lightweight are the development trends of high-speed trains in the world. Air braking technology is the last line of defense to ensure the safety and reliability of trains. The complex working environment and huge braking power put forward higher requirements for brake disc configuration and material. Carbon-ceramic composite materials have the characteristics of large specific heat capacity, thermal shock resistance, lightweight and high temperature resistance, and are considered to be high-performance friction materials. By imitating the distribution of animal and plant nutrients transportation pipelines, a carbon-ceramic composite brake disc structure with #-shaped heat dissipation ribs was designed that take into account the anisotropy of the thermal conductivity of carbon-ceramic composite materials. The branched rib structure realizes rapid heat transmission in the disc material, thereby achieving high efficiency and uniform temperature distribution, prevents the concentration of heat generated by friction, which can reduce the maximum temperature value under braking conditions. Then combined with the shape optimization and size optimization design of the local heat dissipation ribs of the brake disc. Further research on the uniform temperature performance and heat dissipation under emergency braking conditions of 400km/h was carried out. The LSR model was used to analyze the different outlet angle, inlet angle and number of the cooling ribs in the same reference flow field. By comprehensively considering parameters as the average maximum temperature, convection heat transfer coefficient, an optimal design that balances cooling efficiency and aerodynamic loss is obtained.

Optimization and design of new configurations in the field of engineering became faster and more accurate by improving three dimension modeling software and computational fluid dynamics methods. Exhaust manifold of the marine diesel engine, which transfers hot gases from cylinders to the turbocharger, has a problem with extreme thermal gradients and crack creation. In order to improve the heat transfer and prevent crack occurrence at the detected critical points, new configurations in geometrics design for exhaust manifold were studied in this paper. Flow simulation of thermal analysis was performed in ANSYS CFX by using Rensselaer Polytechnic Institute wall boiling model for subcooled boiling at the low pressure. Analysis indicated the single channel configuration, performed by removing output-separating wall on hot gases side, provide more uniform temperature distribution in the manifold body. Results showed the correct operation of new manifold geometry that reduces the maximum temperature of the body up to 27.36% and controls the extreme (amount of) thermal gradients.

Modeling studies have been conducted to determine the temperature field in a lead‐acid cell contemplated for load‐leveling applications, with daily duty cycles and a weakly equalization charge. The results show that under the proposed daily cycling and without a forced cooling, a maximum temperature rise of 16°C can be expected at the center of a proposed 9.76 kW‐hr cell . For such tall lead‐acid cells, reduction of cell length by about one‐half would reduce the temperature rise by 7°–8°C without employing forced cooling. Conventional water cooling at the cell terminals has little effect in lowering the cell maximum temperature. Moreover, cooling may induce a large temperature gradient in the vertical direction of the cell, which may cause a nonuniform current distribution over the electrode leading to a gradual loss of cell capacity and cycle life. Practical cells in use often incorporate “air lift pump” that facilitates electrolyte stirring or an electrolyte circulation design to minimize the extreme temperature gradients. Gassing during the weekly equalization charge of loading‐leveling cells may also enhance internal heat transfer, causing a more uniform temperature distribution. After the weekly equalization charge, the cell temperatures resume their initial values at the end of the rest period.

Due to a lack of prototypical experimental data, little is known about the off-normal behavior of recently proposed divertor jet cooling concepts. This article describes a computational fluid dynamics (CFD) study on two jet array designs to investigate their susceptibility to parallel flow instabilities induced by non-uniform heating and large increases in the helium outlet temperature. The study compared a single 25-jet helium-cooled modular divertor (HEMJ) thimble and a micro-jet array with 116 jets. Both have pure tungsten armor and a total mass flow rate of 10 g/s at a 600 °C inlet temperature. We investigated flow perturbations caused by a 30 MW/m2 off-normal heat flux applied over a 25 mm2 area in addition to the nominal 5 MW/m2 applied over a 75 mm2 portion of the face. The micro-jet array exhibited lower temperatures and a more uniform surface temperature distribution than the HEMJ thimble. We also investigated the response of a manifolded nine-finger HEMJ assembly using the nominal heat flux and a 274 mm2 heated area.For the 30 MW/m2 case, the micro-jet array absorbed 750 W in the helium with a maximum armor surface temperature of 1280 °C and a fluid/solid interface temperature of 801 °C. The HEMJ absorbed 750 W with a maximum armor surface temperature of 1411 °C and a fluid/solid interface temperature of 844 °C. For comparison, both the single HEMJ finger and the micro-jet array used 5-mm-thick tungsten armor. The ratio of maximum to average temperature and variations in the local heat transfer coefficient were lower for the micro-jet array compared to the HEMJ device.Although high heat flux testing is required to validate the results obtained in these simulations, the results provide important guidance in jet design and manifolding to increase heat removal while providing more even temperature distribution and minimizing non-uniformity in the gas flow and thermal stresses at the armor joint.

Fuel layered-distribution sintering (FLDS) is a technology that can effectively reduce fuel consumption and achieve a more uniform temperature distribution within the sintering bed compared to traditional iron ore sintering. In this study, the melting quality index, combined with the maximum temperature and the duration of melting temperature, are used as performance indicators to investigate the effects of coke size and oxygen content on sintering characteristics under layered fuel distribution conditions. The results indicate that increasing the oxygen content can enhance the velocity of the flame front in the sinter pot, thereby accelerating the sintering process. However, excessive oxygen content may lead to fluctuations in the quality of the sinter. Small coke sizes provide higher melting quality in the upper region of the sinter pot, while large coke sizes perform better in the lower region. For a 600 mm sintering bed layer, an oxygen enrichment time of 6 min with oxygen concentration of 27% and coke particle diameter of 2.0 mm can balance sintered ore quality, sintering time, and flame front speed, ensuring the yield of sintered ore. These findings provide an effective pathway for energy saving and emission reduction in iron ore sintering plants.

The continuing increase in CPU and GPU performances can be attributed mostly to the rise in frequency, scaling of chip area (bigger dies), advancements in thermal management, and improvements in thermal design power, among other factors. Over the past two decades, the size of a typical GPU die has increased from 100 mm2 to ∼800 mm2 in the year 2020. Silicon-based single-phase embedded microchannels with a large area of 30 mmx30 mm, featuring three-dimensional (3D) manifold (MF) μ-coolers, can potentially remove heat and minimize pressure drop. However, previous computational fluid dynamics (CFD) simulation findings indicated considerable temperature nonuniformity resulting in increased thermal resistance and maximum temperature. The primary cause of temperature non-uniformity is the abrupt flow acceleration at the entrance and sudden deceleration at the end section of the 3D-manifold inlet channels. This leads to a significant temperature rise in the middle region of the microcooler. In this study, we introduce innovative microcooler designs and conduct extensive computational fluid dynamics (CFD) simulations to achieve low thermal resistance, low-pressure drop, and crucially, uniform temperature distribution across the entire surface area of the microprocessor. To deal with this issue, our initial approach involved integrating converging inlet and diverging outlet channels into the 3D manifold. Although this method effectively dealt with the nonuniformity throughout the u-cooler’s area, it still resulted in a large pressure drop. Consequently, we implemented a narrow opening at the end of the inlet channels in the 3D manifold. This allows a portion of the coolant (50–80%) to bypass the microchannels in the cold plate to the exit plenum. As a result, the pressure was reduced by ∼66% compared to the conventional 3D manifold microchannel cooler.

Thermal conduction and mechanical stresses in through silicon via (TSV) structures in three dimensional system in package (3D SiP) under device operation condition were discussed. A large scale simulator, ADVENTURECluster® based on finite element method (FEM) was used to simulate the effects of voids formed inside Cu TSVs on the thermal conduction and mechanical stresses in the TSV structure. The thermal performance that was required in 3D SiP was estimated to ensure the reliability. Simulations for thermal stresses in the TSV structure in 3D SiP were carried out under thermal condition due to power ON/OFF of device. In case that void was not present inside the TSV, the stresses in TSV were close to the hydrostatic pressure and the magnitude of the equivalent stress was lower than the yield stress of copper. Maximum principal stress of the Si chip in the TSV structure for the case without voids was lower than that of the bending strength of silicon. However, the level of the stresses in the Si chips should not be negligible for damages to Si chips. In case that void was present inside the TSV, stress concentration was occurred around the void in the TSV. The magnitude of the equivalent stress in the TSV was lower than the yield stress of copper. The magnitude of the maximum principal stress of the Si chip was lower than that of the bending strength of silicon. However, its level should not be negligible for damages to TSVs and Si chips. The stress on inner surfaces of Si chip was slightly reduced due to the presence of a void in the TSV.