1. DESIGN AND CONSTRUCTION OF AN INDUCTION FURNACE (COOLING SYSTEM) Presented by MG THANT ZIN WIN Roll No: Ph.D-M-7 18 th Seminar 13.10.2004 Supervisors : Dr Mi Sanda Mon Daw Khin War Oo

2. Consider the Flow Velocity of Induction Coil at Maximum Melting Point Fig – Sample induction coil

3. Assumption 1.Steady state condition. 2.One-dimensional heat transfer by conduction across the cylindrical wall. 3.Molten metal are pure cast iron and the highest melting point is 1600˚C. 4.The induction coil is also supplied the electrical current 1900 A, AC voltage 650 V, power 160 KW and frequency 880 Hz. 5.Constant properties exist. 6.Neglect the interfacial contact resistance.

4. Determining the Thermal Equivalent Circuit Fig – Temperature distribution for a composite cylindrical wall

5. Thermal equivalent circuit of the problem, Heat transfer rate,

6. Calculating Heat Transfer Rate of the Side of Induction Coil By substituting the desire values in the above equation, k A = 32-85 W/m  C at 230  -1000  C, k B = 0.166 W/m  C at 51  C, k C = 12.604 W/m  C at 27  C, T s,1 = 1600  C T s,4 = 74  C from practical measuring data, L 1 = 0.46228 m r 1 = 0.12 m r 2 = 0.193336 m r 3 = 0.194836 m r 4 = 0.1973336 m where,

7. Calculating Heat Generation Rate Inside the Induction Coil due to the Electrical Resistance Heating In R value at 20˚C, 0.003183 Ω In R value at 60˚C, 0.00365455 Ω Copper coil area Copper coil volume where, L 2 = the length of induction coil = 20.96 m α = temperature coefficient for copper = 0.004 Ω/Ω/˚C Heat generation rate,

8. Total Heat Transfer Rate Total heat transfer rate = Heat transfer rate passing through the refractory lining + Heat generation rate due to the electrical resistance heating = (60.5129 + 13.1929) KW = 73.7058 KW

9. Specifying the Mass Flow Rate of Induction Coil For imcompressible fluid, where, c p = 4.179 kJ/kg  K at T m,o = 54  C from practical measuring data T m,i = 28  C from practical measuring data Fig – Schematic layout of induction coil

10. Flow velocity, Finally, Flow velocity of induction coil = 2.99 m/s #

11. The Resulting Flow Velocity compare with Reference : BCIRA Broad Sheet Ref: In BCIRA Broad sheet, Alvechurch, Birmingham B48 7QB, 1978 Flow velocity All cooling passages should be designed so that the flow velocity is not less than 1 metre per second, to prevent any suspended solids settling-out in the system. So, our flow velocity is over 1 m/s. It may be possible.