CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   Fluent Multiphase (https://www.cfd-online.com/Forums/fluent-multiphase/)
-   -   Suspension velocity & pressure drop in slurry flow analysis (https://www.cfd-online.com/Forums/fluent-multiphase/228811-suspension-velocity-pressure-drop-slurry-flow-analysis.html)

 abc197 July 15, 2020 23:28

Suspension velocity & pressure drop in slurry flow analysis

Dear all. I am working on slurry flow (Water+sand) modelling in Ansys Fluent in a 3D horizontal pipe. Solid volume fraction is 20%. I ma interested to find out the suspension velocity of fluid in this case. That is the point where all sand particles are flowing with the water and none of particles are settled at bottom. In starting with Eulerian 2 phase granular model, . My issues are
(1) How do I verify in Fluent that suspension velocity has been achieved. Is it by looking at sand velocity profile or solid fraction profile throughout the pipe or something else. Can we track the sand particles path in result. So we know the moment it is suspended in water. Basically how do we know sand floating in water and what velocity.
(2) Is it true that we have to patch sand volume initially to bottom region of pipe. Is patch at all mandatory, because what if sand and water entering uniformly at the inlet. or what of Initially there is no sand in pipe. Can we get result without patching.
(3) I used tried with turbulence k-e realizable and RNG model without patching. I am getting same velocity distribution throughout the pipe for sand and water for staedy state case. Also solid vol fraction at any cross-section remains same throughout pipe. Bulk of sand at bottom. Which cant be right.
(4) In results, in some regions, solid vol. fraction found exceeding the input asigned value.

Any help is much appreciated. :)
with best regards

 abc197 July 19, 2020 05:17

2 Attachment(s)
After performing for steady state, without patching as sand enters with water. It is a 2.5 m long pipe with pipe dia of 25 mm. Eulerian-granular, 2-fluid phases (one granular phase) is used with k-epsilon turbulence.

I am getting sand vol. fractions and sand velocity profiles as shown. In first row, sand vol fraction contours are shown for inlet, middle and outlet of pipe. In second row, sand velocity contours are shown for inlet, middle and outlet of pipe. Expectation is to see the sand cluster to move to come to upside in cross-section as it moves along with water. I cant see that as of now. Not sure where the problem could be.

I appreciate any suggestions regarding improving.