| Autor: |
Hanna Gladki, Michael R. Poirier, Phillip O. Rodwell, Mike R. Powell |
| Rok vydání: |
2000 |
| Předmět: |
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| Popis: |
Publisher Summary Sludge resides on the floors of many U.S. Department of Energy (DOE) radioactive waste storage tanks. Sludge is composed of fine-grained particles cohesively bonded together by both colloidal and mechanical forces. Retrieval of sludge from these tanks is difficult—access is limited and radiation exposure concerns require remote operation. This chapter discusses the relationship between sludge properties and the mixing system requirements in order to improve the design of a sludge retrieval system. Tests are performed in which simulated radioactive sludge that is suspended and mixed using submerged, horizontal fluid jets. The fluid jet is generated by a free jet flow agitator (FJFA). Tank diameters used for the tests were 0.45 m, 1.8 m and 5.7 m. Sludge shear strengths range from 10 Pa to 2000 Pa. The shear stress needed to mobilize most of the sludge simulants is correlated to the undisturbed sludge strength. The average wall shear stress generally required to mobilize 80% of the sludge is approximately 5.0% of the measured shear strength. Mixing system performance is predicted by estimating the fraction of the tank floor where the applied shear stress exceeds the sludge's estimated critical shear stress. Computational modeling of the floor's shear stress distribution in the 5.7 m diameter tank test, yields sludge mobilization predictions that are reasonably consistent with the results. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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