Explore the vast range of titles available.

Grinding is a crucial process in machining workpieces because it plays a vital role in achieving the desired precision and surface quality. However, a significant technical challenge in grinding is the potential increase in temperature due to high specific energy, which can lead to surface thermal damage. Therefore, ensuring control over the surface integrity of workpieces during grinding becomes a critical concern. This necessitates the development of temperature field models that consider various parameters, such as workpiece materials, grinding wheels, grinding parameters, cooling methods, and media, to guide industrial production. This study thoroughly analyzes and summarizes grinding temperature field models. First, the theory of the grinding temperature field is investigated, classifying it into traditional models based on a continuous belt heat source and those based on a discrete heat source, depending on whether the heat source is uniform and continuous. Through this examination, a more accurate grinding temperature model that closely aligns with practical grinding conditions is derived. Subsequently, various grinding thermal models are summarized, including models for the heat source distribution, energy distribution proportional coefficient, and convective heat transfer coefficient. Through comprehensive research, the most widely recognized, utilized, and accurate model for each category is identified. The application of these grinding thermal models is reviewed, shedding light on the governing laws that dictate the influence of the heat source distribution, heat distribution, and convective heat transfer in the grinding arc zone on the grinding temperature field. Finally, considering the current issues in the field of grinding temperature, potential future research directions are proposed. The aim of this study is to provide theoretical guidance and technical support for predicting workpiece temperature and improving surface integrity. The temperature field is divided into uniform continuous segment and nonuniform discontinuous counterpart. The heat source distribution model is summarized for different cutting depths. The energy proportional coefficient and convective heat transfer coefficient models are summarized. The application and implementation of temperature field and grinding thermal mode are summarized.

Micro-holes are key components of printed circuit boards (PCBs) that enable the interconnections of different signal layers, and their surface quality is crucial to signal transmission performance. However, in the process of PCB micro-hole drilling, an overly high temperature can cause resin melting and the chips to stick to the tool, resulting in micro-hole quality problems such as plugging, burrs, and nail heads. Therefore, this paper studies the heat transfer trends and temperature distribution characteristics of PCBs in drilling processes. Based on the heat source method and finite difference method, a mathematical model of the PCB micro-hole drilling temperature was established first. Through experiments, the drilling force and temperature under different processing conditions were measured, and then, the heat distribution coefficients of a copper foil and an epoxy fiberglass cloth were obtained with a genetic algorithm. Next, the theoretical temperature of PCB drilling was calculated. Finally, the temperature model was verified by comparing the calculated and measured temperatures; the relative error was within 15.95%. The proposed mathematical model accurately describes the PCB micro-hole drilling temperature and provides technological support for improving the quality of micro-holes.

To better predict the cutting temperature during 3D ultrasonic vibration–assisted turning, this paper establishes a mathematical model for calculating cutting heat based on the classical theory of heat distribution, and the heat dissipation in the discontinuous cutting process is considered. The accuracy of the model was finally calibrated experimentally. The effects of turning speed, depth of cut, feed rate, and amplitude of the tool nose on cutting temperature were analyzed. The results indicate that turning speed significantly affects the cutting temperature, and the amplitude of the tool nose has the slightest effect on cutting temperature. In the range of lower turning speed, the heat source of the shear plane plays a dominant role in workpiece temperature; in the range of higher turning speed, the heat source motion and heat distribution coefficients play a dominant role.

This study deals with ANSYS/Thermal analysis of the heat dissipation system of a resonant power converter for a non-starting air conditioner compressor for commercial vehicles, predicts the heat sink saving effect, and proves feasibility through experiments. The thermal analysis model was set with the heat sink and peripheral components of the resonant power converter, and the ambient temperature was 25 °C under natural convection conditions, and ANSYS/Thermal simulation was performed using the heat flux value of the heating part including the MOSFET. As a result of performing ANSYS thermal analysis according to the above conditions, the heat sink of the resonant power converter showed a maximum heat distribution of 28.4 °C, and the maximum temperature of the resonant power converter with the heat sink was about 59.2 °C. According to this result, the horizontal size (L) of the heat sink selected at the beginning of development was reduced to 210 mm as a result of ANSYS analysis. A DSP-based experiment was conducted at maximum output power condition (2.5 kW) using a reduced 210 mm heat sink and the original 250 mm heat sink. As a result of the experiment, the same temperature distribution was measured in the low voltage side bus bar (LVPL) of each heat sink system, the switching element part, and the power driver, except for the high-frequency (HF) transformer. When the heat sink is reduced, the temperature of the HF transformer is about 8 °C higher than that of the original heat sink, so a transformer with a slightly higher capacity should be selected. This study is significant in that it is possible to provide information on heat sink reduction by predicting the temperature of about 30℃ for heat sink and about 55 °C for MOSFET using only ANSYS analysis without experimentation. Using the above results, the resonant current of the transformer and the output voltage and output current of the resonant power converter were finally measured for 2.5 kW, and it was confirmed that the output voltage of 250 V was stably generated at the battery voltage of 24 V.

This paper investigates the heat distribution on the movable vertical arm of the CZ-12 launch vehicle within the rocket plume impact field in the three-horizontal test launch mode. A model for the different flight altitudes of rocket plume impact on the different angles of the vertical arm was established based on the three-dimensional Navier–Stokes equations and a realizable k−ε turbulence model. The numerical results were compared with experimental data and schlieren images from literature to verify the effectiveness and accuracy of the established numerical model. The results show that when the flight altitude of the rocket is between 30 m and 40 m, the worst heat environment occurs on the front and bottom of the vertical arm. Before reaching a flight altitude of 30 m, a smaller rotation angle of the vertical arm leads to higher maximum temperatures at these two regions. After reaching a flight altitude of 40 m, a larger rotation angle of the vertical arm results in higher maximum temperatures. The top of the lower frame structure is not directly affected by the rocket plume before reaching a flight altitude of 30 m. After reaching a flight altitude of 40 m, a smaller rotation angle of the vertical arm results in higher heat loads on the frame. The results of this study can provide a basis for designing targeted thermal protection for vertical arms. They also contribute a new idea for reducing the thermal load on the vertical arm, which is to rotate the vertical arm to the appropriate angle according to the rocket takeoff altitude. Meanwhile, these research findings will supply a relative reference for researchers who are concerned about other facilities in the surrounding area.

Electrical discharge machining (EDM) is a non-conventional method of machining hard materials with intricate shapes. Near-dry electric discharge machining (ND-EDM) is an advanced method of EDM which is eco-friendly and is more efficient in terms of material removal rate (MRR) than traditional EDM. In this research, an approach has been made to perform a new electrical discharge machining operation on EN-31 steel which utilizes metallic powder as an additive along with a gaseous dielectric (for example air) in ND-EDM. This advanced method of machining is known as powder mixed near-dry EDM. This study involves modeling for output process parameter—Material Removal Rate. The mathematical model was developed using the approach of Gaussian heat distribution. FEM modeling was done on ANSYS WORKBENCH 16.0 module. The experiments were performed and comparative study was done between the results obtained by modeling and experiments. The maximum experimental MRR was 7.68 mm3/min, and the error percentage between experimental, mathematical and FEM was under 30%. It was concluded that the modeling was done successfully and results obtained do comply with the methodology of the research.

Thermotherapy is considered to have potential beneficial effects when applied to wounds. Of particular relevance to this research are wounds that have dropped in temperature due to regional anaesthesia. This study is aimed at developing a normothermic system comprising of a heat patch controlled by external hardware. The study is divided into three parts: (i) the analyses of the skin temperature that form the foundation of the system; (ii) the development of an efficient wearable heat patch incorporating thermoelectric elements to electrical and thermal conductive textiles; and (iii) the hardware development to control the current flow to the thermoelectric elements thus managing the temperature of the heat patch and conserving current. It was observed that a distance of 3 cm between the thermoelectric elements provides ideal heat distribution relative to the surface area. The system allowed for an 80% reduction in current, while maintaining the temperature of the heat patch at the required thermophysiological skin temperature. Future studies will include development of a temperature sensor identifying the real-time temperature of the wound; and circuitry for switching the polarity of the thermoelectric elements. The cooling capabilities of the thermoelectric elements can be applied to wounds that have increased in temperature.

This work presents experimental analysis on the local heat flux distribution for a prismatic lithium-ion battery at various charge/discharge rates. Experimental setup for a large prismatic lithium-ion battery thermal testing is developed, and experimental investigations of the thermal dissipation of lithium-ion battery are conducted under various charge/discharge rates to provide more information on battery heat generation. The aim of the present study is to evaluate the heat generated by the electrochemical reaction inside a lithium-ion cell during numerous charging/discharging cycles until reaching steady state. In this paper, the distribution of temperature is presented for a prismatic Li-ion battery at different operating conditions. The results show that a higher battery temperature is obtained at the beginning of the charge cycle and the lower temperature is reached at the end of charge cycle and the beginning of discharge cycle. Furthermore, it is observed that the increase in charge/discharge current rate increases the battery temperature, the generated heat flux and the part of the irreversible heat compared to the reversible heat. It can be observed that at C-rate of 3C irreversible heat reaches 80% of the total generated heat.

Widder’s representation and inversion theorems are proved for the solutions of the Ornstein–Uhlenbeck and Hermite heat equations. This allows to obtain a complete solution to the existence and uniqueness theorem for the initial heat distribution problem in the framework of the aforementioned heat equations.

In order to increase the efficiency of Parabolic Trough Collectors (PTCs) in solar thermal applications, this study proposes an optimal design for these devices. Non-uniform heat distribution, which lowers thermal efficiency and results in material stress, is a major drawback of traditional PTC systems. In order to improve solar flux concentration and uniformity, a novel arrangement that incorporates a plano-convex lens above the receiving tube has been devised. Heat flow distribution and system behavior under different environmental circumstances were analyzed using SolTrace optical modeling and computational fluid dynamics (CFD) simulations. A steady-state analysis of turbulent, incompressible flow with mixed convection was part of the research methodology. Furthermore, a discrete ordinate technique was used to describe the thermal radiation between the absorber tube and the glass envelope. An accurate evaluation of improvements in solar flux concentration brought about by lens integration was made possible using SolTrace simulations. Wind load testing guaranteed operational stability in harsh circumstances, while structural analysis verified that the reflecting sheets deformed minimal under loading. According to the results, the plano-convex lens raises the concentration of solar flux, which increases structural stability and thermal efficiency. A more consistent temperature distribution along the receiver tube was shown by integrating SolTrace for optical validation. The system's long-term operational viability was validated by structural simulations, which confirmed its resilience in harsh environmental circumstances. By putting out an affordable strategy for enhancing the longevity and efficiency of PTC systems, this study advances renewable energy and speeds up the shift to sustainable energy sources.