SIMULATING THE BLISTER TAP HOLE CONCEPT DESIGN USING CHT - - PowerPoint PPT Presentation

SIMULATING THE BLISTER TAP HOLE CONCEPT DESIGN USING CHT CAPABILITIES IN STAR-CCM+ V5.02.009 Bateman Engineering Projects, Pyro Technologies, SA

2011 STAR European Conference: 22 & 23 March, Netherlands

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CONTENTS

• Current Blister Tap Hole:
• Numerical CFD Models (x4).
• Conclusions.
• Bull Nose Blister Tap Hole:
• Numerical CFD Models (x3).
• Conclusions.

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Current SiC insert blister tap hole configuration (oxygen fuel burner effect included).

1. Steady state simulation – clay in tap hole with the Oxygen Fuel Burner (OFB) off. Results not shown. Aim: Establish the initial conditions for the subsequent transient runs. 2. Transient simulation – clay in tap hole with the OFB on (duration = 37 minutes). Determine the OFB heat flux required to incite the 6 thermocouple positions to correspond with the measured thermo- couple values (benchmark). 3. Transient simulation – blister flowing in tap hole with the OFB on (duration = 62 minutes). Simulate the transient tapping process to correspond with measured thermocouple values / trends. 4. Transient simulation – clay in tap hole with the OFB off (duration = 62 minutes). Simulate the cool-down cycle after transient tapping to correspond with measured thermocouple values / trends.

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Current Blister Tap Hole – Thermocouple Positions

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Clay in Tap Hole – Temperature (OFB on @ 34.8 kW/m²)

T1 T2 T3 T4 T5 T6

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Clay in Tap Hole – Temperature (OFB on @ 34.8 kW/m²)

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Blister in Tap Hole – Temperature (OFB on @ 34.8 kW/m²)

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Blister in Tap Hole – Temperature (OFB on @ 34.8 kW/m²)

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Clay in Tap Hole – Temperature (OFB off)

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Clay in Tap Hole – Temperature (OFB off)

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BTH7 – Summary of OFB on / OFB off conditions

• Measured- & predicted CFD temperature

values at the end of each transient cycle:

Measured vs. Predicted T1 [° C] T2 [° C] T3 [° C] T4 [° C] T5 [° C] T6 [° C] T/C (clay & OFB on) 242.3 91.3 50.5 43.4 47.7 64.7 CFD (clay & OFB on) 242.5 142.0 98.9 81.2 78.4 89.8 T/C (blister & OFB on) 990.3 882.2 825.3 801.4 745.0 798.8 CFD (blister & OFB on) 961.7 911.3 963.9 971.1 906.3 923.8 T/C (clay & OFB off) 399.4 431.8 438.9 478.8 460.9 529.6 CFD (clay & OFB off) 355.7 389.8 426.5 446.0 451.8 463.9

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Current Blister Tap Hole – Conclusions

• Differences in measured vs. predicted values attributed to:
• Thermocouple positions & measurements maybe not exactly the

same in the SiC insert (on-site vs. models).

• Temperature CFD results are higher due to constant thermal material

properties in all directions (isotropic).

• Thermal resistances between region interfaces not incorporated in

the numerical models (conjugate heat transfer).

• However: Trends of graphs predicted more or less correctly for each

transient stage.

• Next step: Apply oxygen fuel burner boundary condition to the new

bull nose blister tap hole concept. Predict thermal behaviour before actual installation earlier this year (March 2011).

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Bull Nose High Alumina insert blister tap hole configuration (oxygen fuel burner effect included).

1. Steady state simulation – clay in tap hole with the OFB off (results not shown). Establish the initial conditions for the subsequent transient runs. 2. Transient simulation – blister flowing in tap hole with the OFB on (duration = 62 minutes). Simulate the transient tapping process to determine the increase in the maximum monitored SG Iron bull nose- & steel can temperatures. 3. Transient simulation – clay in tap hole with the OFB off (duration = 62 minutes). Simulate the cool-down cycle after transient tapping to determine the decrease in the maximum monitored SG Iron bull nose- & steel can temperatures.

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Blister in Tap Hole – Temperature (OFB on @ 34.8 kW/m²)

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Blister in Tap Hole – Temperature (OFB on @ 34.8 kW/m²)

SG Iron Bull Nose Steel Frame & Can

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Clay in the Tap Hole – Temperature (OFB off)

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Clay in the Tap Hole – Temperature (OFB off)

SG Iron Bull Nose Steel Frame & Can

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BTH8 – Summary of OFB on / OFB off conditions

• Predicted CFD temperature values at the end
• f each transient cycle:

Maximum Temperatures for: SG Iron [° C] Steel Can [° C] High Alumina [° C] CFD (blister & OFB on) 483.5 386.1 1394.2 CFD (clay & OFB off) 242.2 362.4 502.8

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Bull Nose Blister Tap Hole – Conclusions

• Maximum monitored temperature value in the SG Iron bull nose with

the OFB on just short of 500 °C after an hour of blister tapping with constant heat flux = 34.8 kW/m² on the front face.

• Maximum monitored temperature value in the steel can hot face

tapered tip just short of 390 °C after an hour of blister tapping (Thermal cycling / induced stresses not investigated).

• Front of the High Alumina insert much hotter with the OFB on, albeit
• nly locally around the tap hole exit.
• All the regions monitored (SG Iron, Steel & High Alumina) heat-up

during the tapping cycle within acceptable operating limits.

• Cool-down cycle with the clay plug; after an hour the SG Iron cooled

down to halve the maximum value when the OFB was on. The Steel Can cooled down by 24 °C, which is less sensitive to either tapping

• r plugged conditions.

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QUESTIONS?

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