MAE PhD Defense – Abhisek Banerjee

Title: High Temperature Heat Extraction from Heat Recirculating Porous Burners

Advisor: Dr.Alexei V Saveliev

Date and Time: April 4, 2019 at 10am

Location: EB3 – 3115

Abstract: Decreasing fossil fuel reserves and increasing demand for energy has driven researchers to explore alternative pathways for energy generation. This has led to the development of various portable energy generating systems based on Stirling engines and thermoelectric generators. Advantages like instant recharge, no moving parts and high efficiency of power generation have lead thermoelectric modules to be used in space applications and remote off-grid power generators. Thermoelectric devices require high-temperature heat to operate efficiently. In the last few decades, researchers have been working to integrate various types of combustion chambers with thermoelectric modules. Considering the advantages of porous medium combustion, integrating these power generators with porous medium burners would lead to efficient energy generating systems. Even though studies have been conducted to extract heat from porous medium combustors, they are mostly limited to low temperature heat extraction. This research investigates high-temperature heat extraction from porous medium burners. This would allow integration of porous medium combustors with portable energy generation systems.

This thesis primarily studies the high temperature energy extraction efficiencies from excess enthalpy porous burners operating with lean fuel mixtures. The optimum positions of heat exchangers operating at high temperature is also identified. 2-D numerical studies are conducted on counterflow burner, reciprocal flow burner and a combination of counterflow and reciprocal flow burner named as reciprocal counterflow burner. Steady-state governing equations are solved to predict the thermal properties of the systems during the oxidation of reactants. The burners are operated with lean mixtures of methane and air in laminar flow regimes. Flame stabilization is studied inside the burner for both with and without high-temperature heat extraction. The heat extraction temperature inside the burner is studied in the range from 300 K to 1300 K. Impact of heat recirculation inside the burner is investigated. It has been found that higher heat extraction temperatures diminish the maximum flame temperatures, and reduces the heat extraction efficiency. The effect of flame location on the heat extraction efficiency is discussed here. The numerical simulation predicted greater high-temperature heat extraction efficiencies for reciprocal counterflow porous burner than counterflow burner by a factor of nearly 15 %. Furthermore, this thesis presents NOx emission characteristics of counterflow burner and reciprocal counterflow burner. The numerical simulation indicates a decrease in the NOx generation with an increase in heat extraction temperature of the burner.

Biography: The author was born in West Bengal, India, a state known for its food and festivities. He went to Kendriya Vidyalaya in many cities across the country. He earned his bachelor in mechanical engineering from Kalyani Government Engineering College in West Bengal. After that, he pursued his masters in the same field from Indian Institute of Technology (I.I.T.) Guwahati. Finally, he joined North Carolina State University to continue his doctoral research in the field of mechanical engineering. He worked under the guidance of Dr. Alexei Saveliev in the domain of combustion.

Outside academics, Abhisek enjoys trying various cuisines, playing and travelling.