| Summary: | 碩士 === 國立中興大學 === 化學工程學系所 === 107 === To extend blast furnace campaign life, it is necessary to understand the temperature distribution and not metal flow behavior in the lower part of the blast furnace under various conditions. In this study, an asymmetric three-dimensional blast furnace hearth was successfully established. The finite volume method was used to discretize the momentum, energy and turbulence models of the space with the second-order upwind difference method, and then the SIMPLE method was used to iteratively solve the algebraic equations to calculate the steady state. After the results, the steady state model was used as the initial condition of the transient model, and the PISO method was used to iteratively solve the algebraic equations. Numerical simulated the temperature distribution, flow behavior and wall shear stress distribution of the blast furnace hearth.
The research used Taguchi method to study the influence of gravity, mass flow rate, hearth porosity and refractory brick heat transfer coefficient on the temperature distribution of blast furnace. The measured temperatures by the thermal couple in the initial furnace of Dragon Steel were used to obtain the optimum physical parameters were gravity-0.98 (m/s2), mass flow rate 90 (kg/s), hearth porosity 0.5, and refractory brick heat transfer coefficient 0.5 (W/mK).
Last, the steady state model was solved in the standard k-ε turbulence mode with the optimized physical parameters, and was used as the initial condition for simulating the transient tapping exchange. The results showed the period from the initial 0s to 20s. When the taphole was exchanged from No.2 to No.1, the wall heat flux on the lower wall of No.2 taphole was decreased from 1502.37 (W/m2) to 1493.82 (W/m2), which was almost unchanged. While the wall heat flux on the lower wall of No.1 taphole was increased from 2926.46 (W/m2) to 4050.14 (W/m2). In the change of wall shear stress, the wall shear stress on the lower wall of No.2 taphole was decreases from 96.38 (Pa) to 5.76x10-3 (Pa). While the wall shear stress on the lower wall of No.1 taphole was increased from 2.09x10-2 (Pa) to 43.63 (Pa). The other, when the taphole was exchanged from No.2 to No.3, the wall heat flux on the lower wall of No.2 taphole was decreased from 1502.37 (W/m2) to 1492.79 (W/m2), which was almost unchanged. While the wall heat flux on the lower wall of No.3 taphole was increased from 2734.27 (W/m2) to 3153.65 (W/m2). In the change of wall shear stress, the wall shear stress on the lower wall of No.2 taphole was decreases from 96.64 (Pa) to 3.66 x10-2 (Pa). While the wall shear stress on the lower wall of No.3 taphole was increased from 4.68 x10-2 (Pa) to 98.46 (Pa).
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