# Cold Model-Based Investigations to Study the Effects of Operational and Nonoperational Parameters on the Ruhrstahl–Heraeus Degassing Process

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## Abstract

The circulation rate of steel is known to play a vital role in the superlative performance of the Ruhrstahl–Heraeus (RH) degasser. Numerous experiments were conducted on a physical model for the RH degassing process, which was established at IEHK, RWTH-Aachen University. The model was developed with a scale ratio of 1:3 to study the RH process. This study is conducted to show the effects of operational and nonoperational parameters on the circulation rate of liquid water in the model. The effects of lift gas flow rate, submerged depth of snorkels, water level in vessel,* etc*. on the circulation rate are studied. The mixing characteristics are studied with the help of current conductivity experiments for different lift gas flow rates and water levels in the vacuum vessel. Finally, the relationship between dimensionless numbers is derived with the help of the experimental data obtained from the cold model.

## Keywords

Water Level Vacuum Pressure Orifice Diameter Circulation Rate Vacuum Vessel## Nomenclature

*ν*Velocity of water through the down leg, m/s

*g*Acceleration due to gravity, m/s

^{2}*d*Diameter of the down leg, m

*ρ*Density of liquid used, kg/m

^{3}*μ*Viscosity of the liquid used, kg/ms

*G*Lift gas flow rate, NL/min (0.167 * 10

^{−4}m^{3}/s)*x*,*y*Coefficients of the equation

*Fr*Froude number

*Re*Reynolds number

*V*_{a}Ratio of lift gas flow rate to the circulation flow rate

*C*Constant of proportionality

- \( v_{\text{p}} ,v_{\text{m}} \)
Velocity of liquid steel and water in industrial unit and model, respectively, m/s

- \( d_{\text{p}} ,d_{\text{m}} \)
Diameter of the down leg for industrial unit and model, respectively, m

- \( G_{\text{p}} ,G_{\text{m}} \)
Lift gas flow rate for industrial unit and model, respectively, NL/min (0.167 *10

^{−4}m^{3}/s)- \( Fr^{\prime} \)
Modified Froude number

- \( u, u_{\text{p}} , u_{\text{m}} \)
Velocity of gas in general and velocities of gas for industrial unit and model, respectively, NL/min (0.167 * 10

^{−4}m^{3}/s)- \( \rho_{\text{g}} \)
Density of gas, kg/m

^{3}- \( \rho_{\text{l}} \)
Density of liquid used, kg/m

^{3}- \( f, f_{\text{p}} , f_{\text{m}} \)
Orifice diameter in general and orifice diameters for industrial unit and model respectively, m

- \( \rho_{{{\text{g}}_{\text{p}} }} \)
Density of argon gas, kg/m

^{3}- \( \rho_{{{\text{g}}_{\text{m}} }} \)
Density of nitrogen gas, kg/m

^{3}- \( \rho_{{{\text{l}}_{\text{p}} }} \)
Density of liquid steel, kg/m

^{3}- \( \rho_{{{\text{l}}_{\text{m}} }} \)
Density of liquid water, kg/m

^{3}- \( v^{\prime} \)
Velocity of water at any point, m/s

- \( p^{\prime} \)
Pressure corresponding to the velocity

*V*at any point, mbar (10^{2}Pa)- \( \bar{v}^{\prime} \)
Mean velocity, m/s

*h*_{sub}Submerged depth of snorkels, mm (10

^{−3}m)*h*_{vac}Water level in vacuum vessel, mm (10

^{−3}m)*p*_{vac}Vacuum pressure, mbar (10

^{2}Pa)*Q*_{cir}Circulation Rate, L/min (0.167 * 10

^{−4}m^{3}/s)*h*′Distance between the height of water in vessel and the point corresponding to the submerged depth, mm (10

^{−3}m)

## Notes

### Acknowledgments

The authors thank IEHK, RWTH Aachen University, Germany, especially Mr. Hasim Fetahi, and IIT Madras for their support and help.

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