An experimental study is carried out on the fundamental aspects of the conjugate, mixed convective heat transfer from two finite width heat sources, which are of negligible thickness, have a uniform heat flux input at the surface, and are located on a flat plate in the horizontal or the vertical orientation. The heat sources are wide in the transverse direction and, therefore, a two-dimensional flow circumstance is simulated

Mixed convection heat transfer from thermal sources mounted on horizontal and vertical surfaces

Application of 8D Methodology: An Approach to Reduce Failures in Automotive Industry

Investigation and implementation of 8D methodology in a manufacturing system

Device handling and testing is one of the process in a Semiconductor Industry. There are such events internally that is related to quality issues. With quality issues rising, this has become the sole purpose for an industry to focus on solving such issues that can result in construction and delivering product output to its customers with its guaranteed quality. One factor in affecting the quality of the products in a semiconductor manufacturing is a mixing event. This paper has focused in applying the 8D methodology in solving the issue. 8D methodology consists 8-steps to be followed by the formed team for problem solving as well as for process improvements to prevent recurrence. An application of Root Cause Analysis (RCA) tools, Fault Tree Analysis (FTA) and 5-Whys Analysis was used in this study. Through these RCA tools used, the root cause of the problem was detected. This resulted in implementing such measures to prevent recurrence of the issue. Results shows no same occurrence of mixing event particularly in pick and place (PnP) handlers. The 8D approach was helpful in solving the issue due to its method that directly pinpoint and identify the problem.

Application of 8D Methodology for Minimizing Test Mixing Event in Semiconductor Test Manufacturing

This paper reports computational research on forced convection air cooling of high thermal conductivity printed circuit boards for dissipating high heat fluxes. Flowing air velocities of 2–6 m/s are used at uniform heat flux values. The full three-dimensional, steady, laminar, incompressible, developing flow are studied. Finite element-based commercially available Comsol Multiphysics 4.3 b software is used to solve Navier–Stokes equations to study the coupling between heat transfer in solids and fluids. Single-layer and multi-layered copper clad boards having thermal conductivities of 8.8 and 40.5 W/m K, respectively, are considered as substrate materials. Effect of thermal conductivity on heat transfer characteristics under forced convection air cooling has been studied. Fifteen aluminum discrete square heat sources of sizes $$15\times 15 \times 5$$
 mm each are mounted on the substrate board that mimics electronic chips on printed circuit boards. Two different thermal conductivity substrate boards mounted with aluminum heat sources are considered for high heat flux values of 4000, 8000, 12,000 $$\hbox {W/m}^2$$
 , respectively. Results of temperature plots show that a multilayer copper clad board is suitable for all high heat flux values considered for the configuration used in this study. Single-layer copper clad substrate board is capable of dissipating heat from electronic components efficiently for the heat flux values of 4000–12000 $$\hbox {W/m}^2$$
 except in case of high heat flux value of 12,000 $$\hbox {W/m}^2$$
 with a velocity of 2 m/s.

Forced Convection from IC Chips on Printed Circuit Boards Generating High Heat Fluxes

This paper has focused on two objectives. The first objective is to study the 8D methodology which is an 8 disciplinary approach. It consist of 8-steps to be followed by quality improvement team for problem solving as well as for product and process improvements. The second objective is to apply the 8D methodology and to analyze its effectiveness. In order to apply the 8D methodology and to analyze its effectiveness a case study was conducted in a small scale manufacturing industry (ISO 9001:2000 certified). The results of the case study show that the 8D methodology is effective. After applying 8D methodology the total rejection for coupling disc part was reduced to 6.57% from 37.95 %.

/pdf/application-of-8d-methodology-for-minimizing-the-defects-in-3w2i6sad2e.pdf

Application of 8D Methodology for Minimizing the Defects in Manufacturing Process: A Case Study

The present work deals with the design procedure, load carrying capacity, mathematical modelling, analysis of worm and worm gear for plug valve application. The plug valves are used in various fluid services applications. It performs well in slurry applications. It is also used in air, gaseous services and oil piping systems and a like applications. In plug valve the main and important function of the worm gear drive is to reliably transmit torque and rotary motion. This paper throws light on addressing these issues by performing experimental work for finding out efficiency of worm gear for plug valve application. The contact stresses of gear tooth are regarded as contributor for the failure of the gear. Thus, the analysis for these stresses has become essential for minimizing the chances of failure. The mathematical model was developed to determine the surface stresses acting on the gear tooth. The testing performance of the worm and worm wheel gear pair is depending upon the torque carrying capacity of the gear pair at the rated speed. The torque testing set up is designed for a worm gear pair with dynamometer. Rigorous trials were conducted by the use of testing set up and readings were used to plot a graph of torque vs speed, which gives the performance of the worm and worm wheel gear pair at the rated speed. The obtained results provide significant information for predicting the static and dynamic performance of worm gear pair. It is observed that there is improvement in efficiency for modified worm gear pair which is used in plug valve application. As the output torque increases efficiency also seen to be increasing.

/pdf/design-analysis-and-experimental-study-of-worm-and-worm-gear-2nj7cr0878.pdf

Design, Analysis and Experimental Study of Worm and Worm Gear Pair for Plug Valve Application

Fast depletion of fossil fuels, rapid increase in the prices of petroleum products and harmful exhaust emissions from the engine are the driving factors in undertaking this research for finding the suitable alternative fuels. The present work deals with the Performance, Emission and Combustion characteristics of Biodiesel derived from acidic oil, which is a by-product of soybean oil refining process. Biodiesel was extracted using two-step esterification and transesterification process from the raw acidic oil. Different blends were prepared on the volume basis and one separate blend was prepared using 2% antigel additives in one of the combination. Tests were conducted with diesel and prepared blends on single cylinder, four strokes, multi-fuel, water cooled engine at compression ratio of 17.5 with different loading conditions. Present investigation indicates reduction in performance parameters as the engine is fuelled with different blends of biodiesel, but significant changes are observed with regard to combustion parameters and reduction in CO, HC. Further, increase in NOx, CO2 is observed during the use of similar blends of bio-diesel. Further the same engine is run with the addition of 2% Antigel Additives in one of the blend, BD20, which has given results which include significant reduction in BSFC, exhaust gas temperature, NOx percentage and integrated heat release rate. Simultaneously it is associated with increase in brake thermal efficiency, HC and CO percentage and peak in cylinder pressure. The prospective results have opened a new avenue of opportunity with regard to conversion of available waste oil to useful biofuel.

/pdf/performance-emission-and-combustion-analysis-of-biodiesel-3m7bf2p8x1.pdf

Performance, Emission and Combustion Analysis of Biodiesel Extracted from Acidic oil: A By-product of Soybean Oil Refining Process

Prominent results of parametric studies on conjugate mixed convection with surface radiation from a vertical channel flush-mounted with multiple non-identical discrete heat sources are presented. T...

Buoyancy-aided conjugate mixed convection with surface radiation from a vertical channel with multiple non-identical discrete heat sources

Numerical simulation studies on combined conduction–convection–radiation from a square-shaped electronic device with multiple identical flush-mounted discrete heat sources have been performed and the prominent results are reported here. The problem geometry comprises a square shaped slab with four symmetrically located flush mounted identical discrete heat sources. The heat generated in the heat sources gets conducted through the slab and subsequently gets dissipated from its boundaries by the combined modes of convection and radiation. Air, a radiatively transparent medium is considered to be the cooling agent. The governing equations for temperature distribution in the entire computational domain are obtained by appropriate energy balance between the heat generated, conducted, convected and radiated. The resulting partial differential equations are solved using finite difference method in conjunction with Gauss–Seidel iterative technique. A computer code is prepared for the purpose. Exhaustive numerical studies are performed to elucidate the effects of parameters like volumetric heat generation, thermal conductivity, surface emissivity and convection heat transfer coefficient on local temperature distribution, peak device temperature and relative contributions of convection and radiation in heat dissipation.

Abhijeet P. Shah

Papers

Application of 8D Methodology for Minimizing the Defects in Manufacturing Process: A Case Study

Design, Analysis and Experimental Study of Worm and Worm Gear Pair for Plug Valve Application

Performance, Emission and Combustion Analysis of Biodiesel Extracted from Acidic oil: A By-product of Soybean Oil Refining Process

Buoyancy-aided conjugate mixed convection with surface radiation from a vertical channel with multiple non-identical discrete heat sources

Conjugate Convection with Surface Radiation from a Square-Shaped Electronic Device with Multiple Identical Discrete Heat Sources