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Preheating and thermal behaviour of a rotating cylindrical workpiece in laser-assisted machining
摘要： Laser-assisted machining is a widely used technique for preheating workpiece to reduce cutting forces and promote machinability in metal machining, thereby enhancing manufacturing quality and productivity. In setting laser-assisted machining parameters, the current practice typically relies on trial-and-error approaches. The uncertainties thereof could lead to adverse outcomes in product manufacturing, thus negating the potential benefits of this machining method. A clear understanding of workpiece thermal behaviour under laser spot heating is pivotal to developing a systematic basis for determining required preheating levels and optimised cutting variables for laser-assisted machining. In achieving this, the experimental methods are recognised to be largely impractical, if not tedious, due to instrument limitations and practicality of suitable non-intrusive measuring methods. Conversely, numerical methodologies do provide precise, flexible and cost-effective analytical options, warranting potential for insightful understanding on the transient thermal impact from laser preheating on rotating workpiece. Presenting such an investigation, this article presents a finite volume-based numerical simulation that examines and analyses the thermal response imparted by laser spot preheating on a rotating cylinder surface. On a rotating frame of reference using the ANSYS Fluent solver, the numerical model is formulated, accounting for transient heat conduction into the cylinder body and the combined convection and radiation loses from the cylinder surface. The model is comprehensively validated to ascertaining its high predictive accuracy and the applicability under reported laser-assisted machining operating conditions. The extensive parametric analyses carried out deliver clear insight into the dynamics of thermal penetration occurring within the workpiece due to laser spot pre-heating. This facilitates appropriate consideration of laser preheating intensity in relation to other operating variables to achieve necessary material softening depth at the workpiece surface prior to setting out on the subsequent machining process. Building upon the data generated, a practically simpler and cost-effective preheating parametric predictor is synthesised for laser-assisted machining using neural network principles incorporating the Levenberg–Marquardt algorithm. This predictive tool is trained and verified as a practical preheating guide for laser-assisted machining for a range of operating conditions.
关键词： numerical thermal modelling,Laser-assisted machining,artificial neural network,validation,thermal treatment
更新于2025-09-19 17:13:59
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Study to improve the efficiency of c-Si material in photovoltaic power plant
摘要： In the present communication, comparison between performance of photovoltaic module with and without duct has been carried out. Different input parameters (namely, ambient air temperature, solar radiation wind speed etc.) have been considered for IIT, Delhi campus. Further, thermal modelling has been derived for the c-Si photovoltaic (PV) module alone and PV module with duct. Different parameters like outlet air temperature from duct and cell temperature have been calculated through MATLAB coding. Due to integration of duct, 3.89% and 125.74% increase in electrical output and equivalent thermal energy have been found in comparison to stand-alone PV module.
关键词： Power plant,Thermal modelling,Photovoltaic module,Equivalent thermal efficiency,Equivalent thermal energy
更新于2025-09-16 10:30:52
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Thermo-fluid-metallurgical modelling of the selective laser melting process chain
摘要： The entire process chain of selective laser melting of Ti-6Al-4V is analysed. First, a thermo-fluid dynamical model is used to investigate the temperature profile during the process and estimate the size and shape of the melt pool. The inclusion of the Marangoni effect improves upon previous work by showing the liquid velocity in the melt pool. Next, this information allows us to estimate the morphology of the grains of a part produced by selective laser melting. Finally, a cellular automata is used to model the microstructural evolution during a uniform heat treatment at the beta transus temperature. It is shown that the model shows good agreement with earlier experimental results.
关键词： selective laser melting,Ti6Al4V,computational fluid dynamics,thermal modelling,microstructural modelling
更新于2025-09-12 10:27:22
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Thermal Influence of the Screw Axial Load on a 1-mm Accuracy Laser Ranged Satellite
摘要： This work explores the role of the screw axial load on the temperature experienced by the mounting set of a Cube Corner Retroreflector (CCR) in a spherical satellite, designed to achieve 1-mm accuracy in satellite laser ranging. Since thermal gradients inside CCRs induce refractive index gradients, changing the optical behaviour, thermal analysis and simulation are needed to ensure the best performances. The screw axial load influences the thermal interface resistances between the rings of the mounting set, changing their thermal behaviour. It is important to study the temperature, not only for the thermal gradients inside a CCR, but also to check that the Kel-F mounting rings do not overcome their maximum operative temperature. Two models have been realized in the commercial software C&R Thermal Desktop?: a model to simulate the entire satellite behaviour and a detailed model to represent the cavity which includes the CCR and its mounting set. Different on-orbit scenarios are analyzed, focusing on the influence of the screw axial load in each of them.
关键词： Satellite laser ranging,Thermal analysis,Cube corner retroreflector,Thermal modelling
更新于2025-09-11 14:15:04