Institutional Digital Repository (Indian Institute of Technology Kharagpu)

Bhattacharyya, Sabyasachi

Static Output Feedback Stabilization and State Consensus Problems of Continuous-Time LTI Positive Systems

Nandy, Anirban

Resource Use Efficiency Assessment of Paddy Growers in Eastern India

Das, Ashok

Modeling and Simulation of Particulate Processes Involving Aggregation and Breakage

Pal, Sourabh

Studies on ZnO Hybrid Nanostructures for Heterojunction Optoelectronic Devices

Khare, Ajay

Application Mapping and Flow-Priority Assignment Techniques for Real-Time Network-on-Chip Design

Roy, Nilanjan

Site Preference and Atomic Ordering in the Pd- and Cd- Rich Intermetallic Compounds

Mohapatra, Subhankar

Effects of Dilution on the Combustion and Emission Characteristics of Kerosene Fuel 
Abstract 
In this present dissertation, numerical studies are carried out to study the effect of dilution in a 
recirculating non-premixed Kerosene fuel combustion. All numerical simulations are performed 
using Reynolds averaged Navier-Stokes approach. Liquid droplets are tracked using Discrete 
Phase Model (DPM). Non-premixed equilibrium combustion model with the Probability density 
function (PDF) is utilized to model the combustion process. Flame structure, lift off characteristics 
and droplet dynamics of kerosene spray flames in various co-flow conditions are computationally 
studied. Three different co-flow conditions are considered: cold flow, cold flow with N2 dilution, 
and simultaneous preheating and dilution. The lift-off height as well as flame width is increased 
with increase in co-flow velocity and dilution. However, beyond a point the flame fails to sustain 
and blows out. Simultaneous dilution and preheating of co-flow case shows a stabilized flame and 
distributed reaction zone.  Numerical analysis on the effect of steam dilution and high pressure on 
kerosene fuel swirl combustion is further carried out. The thermal intensity of 5.37 MW/m3 with 
21.1 kW thermal input is considered for the computational study. The chamber pressure and steam 
dilution in the oxidizer is varied from 1 to 20 atm and 0% to 20%, respectively. The addition of 
steam as a diluent enhances the oxidation rate of CO to CO2. Chemical kinetic study is carried out 
to study the effect of diluents on the combustion chemistry of simpler fuels like methane as well 
as a single surrogate species of kerosene. For low operating pressure conditions, the GRI-3.0 
mechanism gives an excellent prediction. Whereas, for applications like gas turbines and furnaces, 
Aramco-3.0 and Curran mechanisms can be adopted to give good results. The San Diego 
mechanism can be chosen for low computational facility purposes as it shows very good 
predictions for ignition delay and laminar flame speed computations. Experimental and numerical 
study is further carried out using a novel hybrid swirl combustor to analyze different recirculation 
modes in the combustor. The hybrid-swirl, formed from the tangential and central vane air swirl 
inlets, helps in achieving low and uniform temperature throughout and assists in flame anchoring. 
 


Effects of Dilution on the Combustion and Emission Characteristics of Kerosene Fuel

Chattopadhyay, Angshuman

Improving the Titanium and Stainless Steel Similar and Dissimilar Welding by Nonconventional Energy Sources and Processes

Mukherjee, Anwesa

Layered and polyanion based electrode materials for sodium rechargeable 
cells 
Abstract 
Now a day’s sodium ion batteries(SIBs) are emerging as promising alternative of lithium ion battery, owing to similar 
electro-chemistry and high natural abundance. But the inadequacy of suitable anode, attracts researcher’s attention 
towards the development of stable and economically viable high performance anodes. Hard carbon the only active 
anode for SIB, poses very low intercalation voltage which may causes Na-plating like serious issues and raise safety 
issues and also the low initial coulombic efficiency is another associated with this anode. Whereas, Titanium based 
anodes seem to be attractive as negative electrodes for sodium ion rechargeable cells. In view to this layered sodium 
titanate (Na2Ti3O7/NaTO) and poly-anionic sodium titanium phosphate (NaTi2(PO4)3/ NTP) are more attractive among 
researcher, for their low operation redox voltage which making it suitable for high energy density anode together with 
higher structural stability and faster ionic mobility respectively. However, poor intrinsic electronic conductivity of 
NTP and low initial coloumbic efficiency, fast capacity fading associated with NaTO limits their practical use. Various 
strategies have been adopted to address these issues related to both the anodes. These include but not limited to surface 
modification, bulk modification and making composites with carbonaceous additives.  Surface properties of the anodes 
are improved by coating with carbon using different carbon source including citric acid, sucrose, poly-ethylene glycol, 
ploy-vinyl alcohol, poly-aniline, poly-vinyl pyrrolidone etc. Carbon coating is imparted ex-situ, in-situ carbonization, 
polymerization etc.  Factors such as carbon source, quality of the carbon, the thickness of coating, nature of the coating 
play important role to improve columbic efficiency, rate performance and cycling stability by increasing the electronic 
conductivity and making a protective barrier on the material surface. The specific capacity of 76mAhg-1, 107mAhg-
1,119mAhg-1 after 100 cycle is obtained using sucrose, PVA, PEG has been used as carbon source respectively, 
showing a great improvement of cycleability compare to bare NaTO. Again, a discharge capacity of 114mAhg-1 is 
obtained after 100 cycles when it is cycled at 100mAg-1 and after 500 cycle a 1.5Ag-1 current density delivers 82mAhg-
1 of discharge capacity and at a current density of 2mAg-1 a discharge capacity of 78mAhg-1 is obtained for 
NaTO@PaNI anode which justify its improvement in high rate sustainability.  Inert surface coating also proven 
efficient to retard the unwanted side reaction on the electrode-electrolyte interface.  In addition, to impart the structural 
stability of the NaTO, by synthesizing the dopant variants of NaTO anode has been proven effective to improve 
electronic conductivity and variation in unit cell volume enhance the Na+ ion transportation. The impact of making 
carbonaceous composite of NaTO and NTP with rGO and CNT offers faster electronic conduction by lowering charge 
transfer resistance(Rct) and increasing the Na+ diffusion co-efficient by proving a conductive path. The excellent 
electrochemical performance of the composite may be ascribed to the synergetic interaction between the carbonaceous 
additives and the material which introduce some pseudo-capacitive nature into it. The combine effect of structural 
integrity, high electronic conductivity as well as high ionic diffusivity in NTP-rGO10-CNT10 leads to excellent 
electrochemical performance in terms of high specific capacity (124 mA h g-1 at 100 mA g-1), remarkable high-rate 
cycling stability (62.5% capacity retention after 400 cycles at 10 C), and excellent rate capability (87 mA h g-1 at 25C) 
Finally, to investigate the full cell characteristics of these anodes, Na3V2(PO4)3/NVP is chosen as cathode. 
Incorporation of electronegative F atom resulting the increase of nominal voltage of the cathode and as a result energy 
density of the full cell is increased. Tape casting the conventional coating technique doesn’t provide a good mixing of 
active material, binder and conductive agent. Whereas, by adopting an efficient electrode fabrication technique i.e., 
electrophoretic deposition, a good adhered, porous electrode is obtained which provides high rate performance of the 
NVP cathode. Finally, using optimized anodes composition and modified cathode, a reasonable full cell performance 
is obtained. All these electrochemical performances validate the application of above mentioned anodes and cathodes 
in sodium ion based energy storage applications. 
Keywords: Na2Ti3O7, NaTi2(PO4)3, Surface coating, Carbonaceous composite, Doping, Sodium ion cells. 


Layered and Polyanion Based Electrode Materials for Sodium Rechargeable Cells

Basak, Rajesh

Detection, Analysis and Mitigation of Online Public Shaming

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