Shashikant B. Thombre

Liquid feed passive direct methanol fuel cell: challenges and recent advances

This paper provides an overview of technological challenges and recent advances in the liquid feed passive direct methanol fuel cells (DMFC). Important issues viz. species management, thermal management, methanol crossover, sluggish anode kinetics, durability and stability, and cost are discussed in detail. Methanol management, water management, oxygen management, and carbon dioxide management are covered under species management. The present technological status is given and future research directions are suggested.

A real-time simulating non-isothermal mathematical model for the passive feed direct methanol fuel cell

ABSTRACT In order to understand the complex transport phenomena in a passive direct methanol fuel cell (DMFC), a theoretical model is essential. The analytical model provides a computationally efficient framework with a clear physical meaning. For this, a non-isothermal, analytical model for the passive DMFC has been developed in this study. The model considers the coupled heat and mass transport along with electrochemical reactions. The model is successfully validated with the experimental data. The model accurately describes the various species transport phenomena including methanol crossover and water crossover, heat transport phenomena, and efficiencies related to the passive DMFC. It suggests that the maximum real efficiency can be achieved by running the cell at low methanol feed concentration and moderate current density. The model also accurately predicts the effect of various operating and geometrical parameters on the cell performance such as methanol feed concentration, surrounding temperature, and polymer electrolyte membrane thickness. The model predictions are in accordance with the findings of the other researchers. The model is rapidly implementable and can be used in real-time simulation and control of the passive DMFC. This comprehensive model can be used for diagnostic purpose as well.

A comprehensive review on recent material development of passive direct methanol fuel cell

Direct methanol fuel cells (DMFCs) within all types of fuel cells are the most viable alternative to lithium-ion batteries in the portable application and recently attracted much attention. This study reviews on passive DMFC material development with emphasis on to the performance activity, cost, durability and stability aspect. This paper has reported the basic desirable characteristics of each component with their material development. This paper has reviewed all possible materials of passive DMFC component, which can make the passive DMFC compact and feasible energy source in the future.

Nonisothermal Mathematical Model for Performance Evaluation of Passive Direct Methanol Fuel Cells

AbstractA one-dimensional, nonisothermal model for passive direct methanol fuel cells (DMFCs) is developed. The coupled heat and mass transport, along with electrochemical reactions, are considered in the model. Cell performance for different methanol feed concentrations is evaluated. The reason for improved fuel cell performance at increased methanol feed concentrations is investigated and explained. Variations in cell operating temperature, heat generation rate at the anode catalyst layer (ACL), and at the cathode catalyst layer (CCL) are critically analyzed in this connection. It is found that the ACL temperature, referred to as the cell operating temperature, has a crucial effect on passive DMFC performance. The increased cell operating temperature at higher methanol feed concentration is responsible for better cell performance. The results of this work will be useful for optimizing the thermal management and achieving better performance of passive DMFCs.

3D CFD Simulations of Hydrogen Fuelled Spark Ignition Engine

By supporting hydrogen as an alternative fuel to the conventional fuel i.e. gasoline, new era of renewable and carbon neutral energy resources can be introduced. Hence, development of hydrogen fuelled internal combustion engine for improved power density and less emission of NOx has become today’s need and researchers are continuously extending their efforts in the improvement of hydrogen fuelled internal combustion engine. In this work, three dimensional CFD simulations were performed using CFD code (AVL FIRE) for premixed combustion of hydrogen. The simplified 3D geometry of engine with single valve i.e. inlet valve was considered for the simulation. Various combustion models for spark ignition for hydrogen i.e. Eddy Breakup model, Turbulent Flame Speed Closure Combustion Model, Coherent Flame model, Probability Density Function model were tested and validated with available simulation results. Results obtained in simulation indicate that the properties of hydrogen i.e. high flame speed, wide flammability limit, and high ignition temperature are among the main influencing factors for hydrogen combustion being different than that of gasoline. Different parameters i.e. spark advance angle (TDC to 40° before TDC in the step of 5°), rotational speed (1200 to 3000 rpm in the step of 300 rpm), equivalence ratio (0.5 to 1.2 in the step of 0.1), and compression ratio (8, 9 and 10) were used to simulate the combustion of hydrogen in spark ignition engine and to investigate their effects on the engine performance, which is in terms of pressure distribution, temperature distribution, species mass fraction, reaction progress variable and rate of heat release for complete cycle. The results of power output for hydrogen were also compared with that of gasoline. It has been observed that power output for hydrogen is almost 12–15% less than that of gasoline.Copyright

Passive direct alcohol fuel cell using methanol and 2-propanol mixture as a fuel

This article examines the effect of addition of small concentration of 2-propanol on the direct methanol fuel cell (DMFC) in passive mode. The different concentration ratio of the alcohol mixture (methanol +2-propanol) is used with constant methanol concentration and by varying 2-propanol concentration in the solution. The new passive direct alcohol fuel cell (DAFC) performance with different alcohol concentration ratio (ACR) has been compared with conventional passive DMFC. The cyclic voltammetry (CV) test, polarization test, and electrochemical impedance spectroscopy (EIS) are carried out to complete the different aspect of the cell performance. The result shows that DAFC with different ACR yields the better performance than the conventional passive DMFC. In this study, the passive DAFC at 1:0.5 ACR shows the optimum cell performance.

Jatropha and Pongamia Straight Vegetable Oils as an Alternative to Diesel as a Fuel

With the fossil fuel depleting very fast, researchers have concentrated on developing new agro-based alternative fuels, which will provide sustainable solution to the energy crisis. Presently, bio-diesels, which are obtained from trans-esterification of straight vegetable oil (SVO), are being used along with diesel in blends. The transesterification process, which is a costly, time consuming and oil quality dependent process is eliminated in the present study. The straight vegetable oils, namely, Jatropha and Pongamia have been analyzed in details. The trial was conducted on a 4-stroke, single cylinder diesel engine, having compression ratio 17.5:1. The experiments were carried out for fuel consumption and emission levels at various loads and without any engine modifications. The results obtained were comparable to and better than diesel. The CO and NOx emission was found less for Jatropha as well as for Pongamia. The specific fuel consumption (SFC) was found to be low for both Jatropha and Pongamia oil at moderate loads. The brake thermal efficiency was also found to be better for both Jatropha and Pongamia oil as compared to diesel© 2005 ASME