Vilas R. Kalamkar

Making the popular clean : improving the traditional multipot biomass cookstove in Maharashtra, India

The paper presents results of a study conducted to identify and modify the prevalent traditional multipot cookstoves in rural areas of Maharashtra, India. The flaws in the existing traditional stoves were identified through a survey comprising measurement of geometrical features of different specimens in the field and face-to-face interaction with the end-users. The end-users answered a structured questionnaire including the information about existing cooking practices, per day fuel consumption, willingness to adapt to a new stove type and related things. A popular model was then modified to develop an improved multipot cookstove, which was compared against the popular cookstove by conducting a set of experiments. The parameters evaluated during the experimentation were specific fuel consumption, burning rate, thermal efficiency, time taken to do a specific cooking task and CO emissions. It was found that the modifications to the popular stove resulted in increase in thermal efficiency, decrease in burning rate and specific fuel consumption but a decrease of firepower and turn-down ratio. The activity resulted in developing a better cookstoves for the targeted community.

Experimental and CFD analysis to study the effect of inlet area ratio in a natural draft biomass cookstove

The biomass cookstoves have been used in rural areas for the time immemorial. New developments in cookstove design are needed due to cookstoves impact on the user’s health and the environment. This paper presents a novel computational method to understand the working of a cookstove. The effect of inlet area ratio on various performance parameters is studied through experimentation and computational fluid dynamics (CFD). The steady-state model predicts the temperature profile at different locations inside the stove for different inlet area ratios (IARs), which is validated against the experimental data. The combustion phenomenon is simulated using non-premixed combustion and k - ε turbulence models. The critical value of IAR is found to be 0.70, up to which the firepower and flame temperature are increasing. For IAR less than 0.7, the firepower decreases, flame temperature saturates, and the CO emissions continue to rise. Results showed that CFD is a useful tool with adequate accuracy to understand the thermal and emissions behaviour of the cookstove. CFD can be used as an aid to the experimentation for preliminary analysis or as a standalone tool once validated experimentally.

Experimental investigation and optimization of Oxy-Acetylene assisted machining parameters for Nickel based alloy Inconel — 718

This paper presents an experimental investigation of Inconel-718 nickel based alloy using Oxy-Acetylene Assisted Machining (OAAM) process, which is difficult-to-cut at room temperature and then results in disproportionate tool wear and poor surface finish. The workpiece surface is heated just before machining operation starts. This is done using external heat source till the set value of temperature is attained, due to heating the material surface is soften which enhances the material removal rate. The set value of temperature is constant while turning the workpiece surface using temperature control system on conventional lathe machine with the help of tungsten carbide cutting tool. This paper presents the design of experiment based on Taguchi method which is used to find the optimal cutting parameters for surface roughness. In this study, the methodology of L9 orthogonal array, signal-to-noise (S/N) ratio and analysis of variance (ANOVA) is applied to synthesize the effect of these parameters on Nickel based alloy Inconel-718.

Heat and Temperatures in Machining: Effects and Significance

Heat generated in machining is significant to study, as number of technical and economic problems has root into it. The high temperatures on cutting tool needs better understanding of contact processes at tool-chip ,tool-workpiece interfaces. The contact length at tool-chip interface is significant to study as it governs the heat moving to the tool as well as many tribological conditions like stresses, tool wear. Understanding of Tool-workpiece interface is significant as it affects the heat moving to workpiece, tool, chip as well as tool flank wear and major machined surface characteristics. Non-sliding type tool wear mechanisms which are highly sensitive to temperature changes are important to study. The latest trends of using High Speed Machining, Dry and Near Dry Machining, Finish hard turning results in more heat generation demanding significant understanding of effect of heat generated and temperatures.

CFD Code Validation and Qualitative Study of Effects of Tip Clearance Variation on Performance of Transonic Axial Compressor Rotor

The main objective of this work is the validation of Computational Fluid Dynamics (CFD) code used for analysis of transonic axial compressors. NASA Rotor 35 is used here as test case for validation. In this work, computations are performed using parallelized RANS code, to predict the transonic axial compressor rotor flow characteristics. Advection Upstream Splitting Method (AUSM) scheme has been used. A Multiple Frame of Reference approach has been used to model the rotor passage. Spalart-Allmaras turbulence model is used to model turbulence. Multiblock Structured mesh is used. Performance characteristics for the entire range of operation, from maximum mass flow rate till maximum pressure ratio, have been simulated. The results obtained are comparable with experimental data within 5–10% error. Investigations have been carried out to study the effect of varying tip clearance in NASA Rotor 35. The present work is intended to study the clearance flow trajectory as a function of varying tip clearance. The effects of shock/vortex interaction in tip clearance region are also studied. The effects of tip clearance size on the generation and evolution of the end-wall vortical structures are discussed by investigating their evolutionary trajectories. By this study, it is observed that as tip clearance reduces, clearance flow trajectory moves downstream. From this it can be concluded that if tip clearance increases, tip clearance vortices expand. This may help in casing-treatment or tip-treatment to mitigate the loss in the performance, if the tip clearance increases.Copyright