Papers by Keyword: Heat Dissipation

Abstract: Metal Additive Manufacturing (AM) has been established as one of the most promising solutions when producing new components due to its advantages in creating complex geometries and adding new functionality to the parts. An example of the last, is the usage of conformal cooling in the tooling industry to improve the thermal behaviour of components in-service. The application of this solution is even more meaningful when using metallic materials with high thermal conductivities (e.g. Aluminium alloys). These are mainly selected when the final weight is a key factor in the final component performance, compared with other conductive materials like copper alloys. This study presents the improvement of the thermal behaviour of a drilling tool case manufactured in Aluminium. The selected application case lacks the possibility of evacuating the heat produced by an engine. A redesign of the component is presented, considering the advantages of Powder Bed Fusion – Laser/Metal (PBF-L/M). Both passive and active heat dissipation are analysed by including the reticular structure and internal cavities with forced air. The study is performed first at coupon level and later in the redesigned case manufactured by PBF-L/M. Infrared Thermography (IRT) inspections are conducted to investigate the thermal dissipation when heating the components, and also to monitor the cooling down process. A comparative thermal analysis between the initial case manufactured by the conventional process and the redesigned AM case is also presented.

Abstract: Thermal distribution in solar cells has been rarely investigated despite it significant impact on the performance. The current contribution presents a COMSOL Multiphysics 3-D analysis of the electrical and optical photogeneration properties in relation with the heat distribution in InGaN solar cell. For this simulation, we have coupled the “Semiconductor Module”, the “Heat Transfer Module for Solids,” and the “Wave Optics Module” allowing us to calculate the Shockley–Read–Hall heating, the total heat flux, the Joule heating the carrier’s concentration, the electric field, and the temperature dissipation in the InGaN solar cell structure. Despite the fact that the achievements of InGaN solar cells are still mostly at the state of laboratory studies, the current contribution presenting original results on coupled phenomena occurring in the cells makes it possible to highlight new possible guidelines for an improve of their efficiency.

Abstract: There is a need for solutions to provide sufficient cooling from power devices, which produce large amounts of heat. This paper focuses on the influence of design of bifurcated fluid streams to dissipate heat. In this study, a single Y-tubes, a double Y-tubes, and an X-tubes designs are studied numerically under space constraints. For a comprehensive and in-depth performance analysis, both heat dissipation and hydraulic performances are analyzed. The distributions of velocity and temperature in the fluid streams is simulated, also the flow resistances and dissipated heat are calculated. Based on the results obtained, a thermo-hydraulic performance factor is introduced for the designs under study. In addition, the accumulation of undesired substances on the wall surface (fouling) that may influence the heat exchanging capability is studied.

Abstract: The cooling process is an essential aspect while designing for uniform heat transfer between the mold and the molded part. Improper design and placement of cooling channels result in non-uniform cooling and thus results in differential shrinkage and warpage on the final product. The installation of the channels yet plays a crucial role in the cooling of the part. Conforming channels that are placed at an optimum distance from the part to enhance the cooling process. In this paper, the performance parameters of straight drilled channels are compared with the conformal cooling channels for an electric alarm box. The analysis indicates that the conformal cooling method improved and enhanced the cooling process and reduced the defects like warpage and differential shrinkage by 25.5% and 28.0% respectively.

Abstract: This paper deals with the analyzing and comparing the thermal performance of heat dissipation system and other components in the design of E3D liquefier using Finite Element Modeling (FEM) for three different filaments namely Polycaprolactone (PCL), polylactic acid (PLA) and Acrylonitrile Butadiene Styrene(ABS). This work evaluates the influence of airflow generated by means of a fan coupled to the extruder. The printable materials are also taken as variable in this investigation. The heating process should ensure the balance between proper heating of the material and controlling the temperature along the extruding body, so it reaches above 140 degrees in function of raw material on the tip of the nozzle and must be lower at the top of the liquefier for the correct perseveration of the 3D printer and its durability.

Abstract: This is a theoretical investigation on MHD peristaltic flow of Newtonian and Jeffery fluid through an asymmetric channel with the effect of heat dissipation. The present study, we investigate to include heat dissipation, permeability, Schmidt number and heat generation parameter. The velocity, temperature and concentration profiles are performed in entire study. The governing equations are solved by using the lubrication approach and perturbation technique. The temperature, velocity and concentration fields, trapping phenomena and heat transfer coefficient are plotted by using different parameters. The significance of this study that the pressure gradient with different values of permeability gradually increased, where we observed that from the graph, the pressure gradient is lesser in Newtonian compared to the Jeffery fluid. Moreover, In the trapping phenomena the number of bolus greater in Newtonian fluid compared to the Jeffery fluid by using different values of phase difference and magnetic field parameter.

Abstract: The vehicle drive axle is one of the main sources of power loss in drivetrain system, and its improvements can have a significant impact on vehicle fuel economy. Gears churning loss, bearing friction loss and engaging friction loss all make a great contribution to the heat generation. The temperatures of lubricants, the gear tooth contacting surfaces, and the bearing surfaces are critical to the overall axle performance in terms of power losses, fatigue life, and wear. So it is important to understand the heat generation and dissipation in automotive drive axle. However, the quantities of understandings of drive axle temperature is limited and published information is deficient.In this paper, we establish the mathematical model of heat generation and dissipation to investigate the connection between thermal behavior and power loss. Power loss is consist of churning loss, bearing friction loss and engaging friction loss. And also we simulate the model to get the conclusion and then conduct the experiments to verify the correctness of the theories and models.

Abstract: Machining technology has undergone an extensive evolution throughout the last decades in its capability to machine hard-to-cut material. This paper will discuss about the next generation insert with cooling feature coupled with forced coolant in machining Inconel 718. The geometry of the insert was changed in a way which has enlarged the surface area approximately 12% compared to regular insert named as nusselt insert. The idea applied in “nusselt insert” was the relation of increase in surface area to heat dissipation. Forced coolant application has become a way to improve existing metal cutting concepts and improve their current material removal rates without any need for a reengineered machining process.Experiments conducted on the inserts is that the first experiment of its kind in machining technology together with forced coolant and tested in four different inserts. The primary focus of the work was the investigation of the relation between the heat dissipation with an increase in surface area/mass ratio in the cutting interface based on its influence on tool wear. The experimental results showed the nusselt insert have better ability for heat dissipation which has led to significant reduce in tool wear and successfully facing Inconel 718 at v_c 105 m/min, f 0.3 mm/rev and a_p 1 mm where the regular insert had a catastrophic failure at v_c 90 m/min, f 0.1 mm/rev and a_p 1 mm. Nusselt insert has shown to increase MRR significantly compared to regular insert.

Abstract: Friction stir welding (FSW) is an alternative method of joining materials with low melting point, patented in 1991 by the American Welding Institute (UK). This method uses the heat generated by mechanical friction between two moving parts, one is the tool rotates and is fastened on the spindle of a conventional milling machine and the other is the part that is attached and is gagged on the bed of the machine. Among the variables identified as the most important for a successful run of the process are the revolutions per minute (RPM) at which the tool rotates, the speed advance at which the workpiece and the tool design as such moves [1]. In this paper the design of several tools applied to FSW process is studied in specific dissipation of heat generated by mechanical friction between the parts, its relation to tool design and qualities of successful meetings is presented, the methodology to achieve this goal was first identify the possible and applicable materials for the tools, second his respective designs to ensure the right function for operation, and finally define FSW technical parameters (RPM, Head angle, speed advance) for experimental tests. The findings and conclusions attribute a novel analysis in the design of tools for this innovative manufacturing process, in the analysis of the results obtained for each of the assemblies experimentation it was discovered that the use of rings at the parts are not decisive for a good weld even heat dispersion is not good.

Abstract: The intermittent drawbacks due to fluctuating temperature factor inside photovoltaic (PV) cells have clearly affected the overall energy performance especially in stochastic weather conditions. Temperature element in the tropical regions is a crucial factor to be determined based on Standard Testing Condition (STC) and Nominal Operating Cell Temperature (NOCT) correlations. Based on the crucial implication of heat dissipation, this study shares some insights of five level heat contour covering the surrounding temperature, PV surface temperature, PV bottom temperature and 2-level of two feet height located under PV array. The field data in real-time approach has been brought up in line to support the energy balance modelling for PV applications with localized heat contour analysis using statistical evaluations. The regression analysis of the 3471 data sampling for the period of 5 days (7AM till 7 PM) produces very good results with correlation coefficient, R² = 0.97.