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Design of the Centrifugal Compressor Vaned and Channel Diffusers Based on the Given Velocity Distribution
Issue:
Volume 10, Issue 4, August 2022
Pages:
46-52
Received:
5 June 2022
Accepted:
21 June 2022
Published:
4 August 2022
DOI:
10.11648/j.ijmea.20221004.11
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Abstract: Traditional methods of designing channels of turbomachines are focused on the use of simple geometric lines and surfaces, such as a straight line, arc, plane, cylindrical surface, etc. The design is performed according to recommendations based on experimental data. The other way of designing the channels of turbomachines is related to solving the inverse problem of fluid dynamics, when the shape of the surfaces is determined by the given distribution of velocities along the surfaces of the channel. Of course, channels designed in this way can be more efficient than channels designed by the traditional method. This paper describes the design principles for centrifugal compressor diffusers based on physical and mathematical models of the flow of swirling viscous compressible fluid. According to the presented method, the designing diffusers is based on the preseparation condition of the boundary layer along one of the outer surfaces. Numerical and experimental research was performed for vaned and channel diffusers. Comparison of experimental and design characteristics of diffusers and flow parameters in diffusers confirm the high efficiency of the diffuser, which was designed using the presented method and the adequacy of mathematical models with the physical processes of fluid flow in diffusers. A new method of designing the vaned diffusers and channel diffusers with the predetermined velocity distribution on vane surfaces provides an improvement in the gasdynamic characteristics of diffusers compared to traditional geometry diffusers.
Abstract: Traditional methods of designing channels of turbomachines are focused on the use of simple geometric lines and surfaces, such as a straight line, arc, plane, cylindrical surface, etc. The design is performed according to recommendations based on experimental data. The other way of designing the channels of turbomachines is related to solving the i...
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Design and Process Optimization in Die Casting Through Conformal Cooling
Boopathy Janarthanam,
Rushikesh Nanasaheb Patil,
Mayur Laxmanrao Jadhav
Issue:
Volume 10, Issue 4, August 2022
Pages:
53-58
Received:
9 June 2022
Accepted:
12 July 2022
Published:
17 August 2022
DOI:
10.11648/j.ijmea.20221004.12
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Abstract: This study aims to implement the conformal cooling in die casting dies to reduce the cycle time and rejections due to shrinkage porosity. In this paper we have done a flow simulation between conventional cooling and conformal cooling to optimize the cooling time/solidification time reduction and shrinkage porosity reduction in die casting parts where the thick mass area/high wall thickness occurs. In die casting process cycle time Solidification time plays a vital role. In order to optimize the die casting process cycle time, conformal cooling design needs to be introduced in the dies at the thick mass area /variable wall thickness where we are not having any scope in modification of product design to reduce the wall thickness of the part to avoid shrinkage porosity/high solidification time. Apart from solidification/cooling time we can reduce the Shrinkage porosity defect by optimizing the cooling channels from conventional cooling i.e. At which the cooling lines can be manufactured through conventional machining process to conformal cooling i.e. At which the cooling lines are manufacturing through 3D Printing process. Normally in the die-casting process the cavity area solidifies first after that the runner, overflows and biscuit solidifies. Soldification depends upon the thick mass area, where ever thick mass area is there then the solidification is complex.
Abstract: This study aims to implement the conformal cooling in die casting dies to reduce the cycle time and rejections due to shrinkage porosity. In this paper we have done a flow simulation between conventional cooling and conformal cooling to optimize the cooling time/solidification time reduction and shrinkage porosity reduction in die casting parts whe...
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The Origin and Evolution of Welding Principles: A Guide for the Understanding of Welding Engineering for Mechanical Engineers
Issue:
Volume 10, Issue 4, August 2022
Pages:
59-67
Received:
20 July 2022
Accepted:
16 August 2022
Published:
24 August 2022
DOI:
10.11648/j.ijmea.20221004.13
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Abstract: Mechanical engineers require a good, accurate and comprehensive understanding of what welding and welding engineering actually is because many of them are very much involved with the manufacture of welded fabrications. The article provides the mechanical engineer with the subtleties from required thinking, in order to understand, as a whole, the philosophy of welding engineering. In this article/paper, welding, welding engineering and welding principles are explained derived from the origin of welding action, how and why this action came about and further, how it has evolved into the empirical science and technology it is today. There will be an explanation of the role of welding rituals that became the backbone of the methodology. Certain facts regarding welding will be proven in front of the reader, e.g. what is the subtle difference between “welding and welding engineering”, and how do we bring about the welding action? Further, it will be brought home to the mechanical engineer that there must be a “Common Objective”, what is it? The paper will go on to establish some definitions, facts and aspects of welding? Proceeding along as the thought process develops, the article analyses for the mechanical engineer in the various instants of argument, how a particular welding principle came about and should be observed. Further, it will be shown how the welding facts and principles, affect and influence welded fabrication behavior in industry. All of this information and facts are to aid the mechanical engineer to understand welding engineering principles, the article / paper is a guide and is written in that style to teach what is an Empirical Science, already established by the author.
Abstract: Mechanical engineers require a good, accurate and comprehensive understanding of what welding and welding engineering actually is because many of them are very much involved with the manufacture of welded fabrications. The article provides the mechanical engineer with the subtleties from required thinking, in order to understand, as a whole, the ph...
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The Development of a Precise Articulated Bus Prediction Model for Model Predictive Control Algorithms
Beomjoon Pyun,
Jaehoon Jeon,
Jaemin Song,
Hyungjeen Choi
Issue:
Volume 10, Issue 4, August 2022
Pages:
68-81
Received:
31 July 2022
Accepted:
23 August 2022
Published:
31 August 2022
DOI:
10.11648/j.ijmea.20221004.14
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Abstract: This study presents a precise prediction model that can be applied to model-based control logic for the realization of autonomous driving systems (ADS) for bus rapid transit (BRT; articulated buses). When realizing model-based control logic, the more a prediction model is accurate, the greater that control logic will be the robustness. However, a heavy prediction model is not recommended for real-time operation of model based control logic. Therefore, in this study, a revised ‘Multi-axle dynamics model’ is used to develop a prediction model which is considering dominant parts of longitudinal, lateral, and roll dynamics. Consequently, this study shows the process of testing BRT buses (the targets), and designing a prediction model by comparing with the test results. As a result, a BRT prediction model is developed with correlation of 92% or above. Furthermore, the prediction model will be applied in the future to a model predictive control (MPC) algorithm and used to construct ADS for BRT buses. In addition, it is anticipated that the use of this prediction model will contribute to the design of control logic for diverse advanced driver assistance systems (ADAS).
Abstract: This study presents a precise prediction model that can be applied to model-based control logic for the realization of autonomous driving systems (ADS) for bus rapid transit (BRT; articulated buses). When realizing model-based control logic, the more a prediction model is accurate, the greater that control logic will be the robustness. However, a h...
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Electrochemistry and Engineering Study of Molecular Protective-Films to Steel-Alloys
Desmond Teck Ching Ang,
Peter Junk,
Glen Deacon,
Maria Forsyth
Issue:
Volume 10, Issue 4, August 2022
Pages:
82-89
Received:
4 August 2022
Accepted:
23 August 2022
Published:
31 August 2022
DOI:
10.11648/j.ijmea.20221004.15
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Abstract: The syntheses and characterisations of Rare-Earth-Metals (REMs) complexes, via the use of green organic esters such as Pyridinecarboxylate (Pyc) and hydroxylnaphthoate (Hnp) to form stable compounds ie. Lanthanide-hydroxylnaphthoate (Ln-Hnp), have been demonstrated to be the most preferred compounds to form a good protective-film over steel-alloys. The electrochemical techniques of Linear Polarisation Resistance (LPR) and Cyclic-Potentiodynamic Polarisation (CPP) used in the studies demonstrated strong protective properties to the steel-alloys from the E corr-potential and I corr-current. This is because the I corr-current was reduced by many folds when coupons were immersed in NaCl (0.01M) as a control bulk-electrolyte. The data has also confirmed that the Ln-Hnp complexes clearly displayed a mixed-type of protective function. Thus, the overall metal dissolution rate of steel alloys is mitigated and the data also indicated that it has shown a healing mechanistic process building a dense molecular composite-films up to 5-micron thick when alloy-coupons were immersed into the solution containing REMs complexes. The characterisation of in-situ treated surfaces by the use of ATR-FTIR microscopy and Raman spectrum revealed its overall protective characteristics which were discussed in this paper.
Abstract: The syntheses and characterisations of Rare-Earth-Metals (REMs) complexes, via the use of green organic esters such as Pyridinecarboxylate (Pyc) and hydroxylnaphthoate (Hnp) to form stable compounds ie. Lanthanide-hydroxylnaphthoate (Ln-Hnp), have been demonstrated to be the most preferred compounds to form a good protective-film over steel-alloys....
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