Midterm colloquium Pooja Kumari

23 July 2018 14:00 till 14:30 - Location: instruction room H, 3me - By: DCSC

"System Identification of heat transfer dynamics in Oxy-fuel cutting of steel"

Oxy-fuel gas cutting is the most widely applied industrial thermal cutting process due to its various benefits such as low-cost equipment, versatility, and flexibility in terms of manual or mechanized operation etc. It is employed in cutting mild steel plates with thicknesses ranging from 0.5mm to 250mm, to manufacture heavy equipment such as windmills, offshore structures, and structures in high-rise buildings.

In the cutting process, a mixture of oxygen and the fuel gas (here acetylene) is used to preheat the metal to its ignition temperature which, for steel, is 700°C - 900°C (bright red heat) but well below its melting point. A jet of pure oxygen from the cutting torch is then directed into the preheated area instigating a vigorous exothermic chemical reaction between the oxygen and the metal to form iron oxide (slag in general term). The high-pressure oxygen jet blows away the slag enabling the jet to pierce through the material and continue to cut through the material as the torch progresses.

Now, in order to optimize and automate this cutting process of steel, we will be studying various factors such as speed control of the cutting torch to maintain an accurate angled cut, need of preheater to improve quality of cut, the oxygen pressure required to enable the exothermic process sustained and to pierce deeper. Hence to study and implement the above factors, we need to have the knowledge of temperature distributions in the process at any stage.

The objective of the project is to obtain a dynamic model of the oxy-fuel gas process by employing system identification techniques. The integral part is the study of heat transfer dynamics of the process and investigation of the parameters important in oxy-fuel cutting. Furthermore, we choose to model the heat sources in oxy-acetylene flame cutting, and the heat conduction in the steel using a numerical simulation based on the Cell Method. The cell method aims at the numerical formulation of physical theories from the very outset, i.e. without discretizing the differential equations and hence it is suitable for direct computer implementation.

Dr. R. Ferrari