Interconnectivity of Bioceramic Scaffolds with Different Porous Structures and Their Fluid Velocity Distribution Analyzed by Micro-CT Computer Modeling

An impeller blade with a slot structure can affect the velocity distribution in the impeller flow passage of the centrifugal pump, thus affecting the pump’s performance. Various slot structure geometric parameter combinations were tested in this study to explore this relationship: slot position p, slot width b1, slot deflection angle β, and slot depth h with (3–4) levels were selected for each factor on an L16 orthogonal test table. The results show that b1 and h are the major factors influencing pump performance under low and rated flow conditions, while p is the major influencing factor under the large flow condition. The slot structure close to the front edge of the impeller blade can change the low-pressure region of the suction inlet of the impeller flow passage, thus improving the fluid velocity distribution in the impeller. Optimal slot parameter combinations according to the actual machining precision may include a small slot width b1, slot depth h of ¼ b, slot deflection angle β of 45°–60°, and slot position p close to the front edge of the blade at 20–40%.

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Electromagnetic Velometry. I. A Method for the Determination of Fluid Velocity Distribution in Space and Time

Journal of Applied Physics ◽

10.1063/1.1707404 ◽

1944 ◽

Vol 15 (2) ◽

pp. 150-164 ◽

Cited By ~ 30

Author(s):

Alexander Kolin

Keyword(s):

Velocity Distribution ◽

Fluid Velocity ◽

Space And Time

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Numerical simulation of plane flow field and the force on the inner rod induced by planetary motion of the rod string

E3S Web of Conferences ◽

10.1051/e3sconf/202125702057 ◽

2021 ◽

Vol 257 ◽

pp. 02057

Author(s):

Yang Zhang ◽

Shimin Dong ◽

Qin Li ◽

Zhe Wang ◽

Yu Yang ◽

...

Keyword(s):

Flow Field ◽

Velocity Distribution ◽

Secondary Flow ◽

Fluid Velocity ◽

Critical Value ◽

Planetary Motion ◽

Plane Flow ◽

Fluid Force ◽

Narrow Space ◽

The Revolution

In order to a the flow of the plane flow field induced by the inner rod rotates and revolves in the cylinder, the Fluent software is used to numerically simulate the plane flow field of the eccentric annulus generated by the planetary motion of the rod string and based on the superposition principle. The velocity distribution and secondary flow of the two flow fields, as well as the fluid force on the inner rod are analyzed. The calculation results show that the flow field induced by the eccentric rotation of the inner rod and the self-rotation of the outer cylinder is quite different from the planetary motion of the inner rod. When rotation of the inner rod has the same direction with the revolution direction, the fluid velocity distribution near the wall of the inner rod is that the velocity on the narrow space side of the annulus is large, and on the wide space side is small. There is a critical value of eccentricity for secondary flow appears when the eccentricity is greater than this value. When rotation of the inner rod is contrary to the revolution, the fluid velocity distribution near the wall of the inner rod is that the velocity on the wide space side of the annulus is large, on the narrow space side is small. Different eccentricity has obvious secondary flow phenomenon where appears in a wide gap and close to the inner rod. When the inner rod revolves, there is a critical value of eccentricity, the inner rod is pushed outward by the fluid force when the eccentricity is less than this critical value. On the contrary, the inner rod is pushed inward. When rotation and revolution are reversed, the critical value of eccentricity increases, when the rotation and revolution are in the same direction, the critical value of eccentricity decreases.

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Image-Based Simulation for the Mechanical Characterization of Scaffolds

ASME 2009 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2009-206495 ◽

2009 ◽

Author(s):

Bruno Notarberardino ◽

Philippe G. Young ◽

Liang Hao ◽

David R. Raymont ◽

Irene G. Turner ◽

...

Keyword(s):

Mechanical Characterization ◽

Imaging Techniques ◽

Sensitivity Analyses ◽

High Resolution Imaging ◽

Porous Structures ◽

Micro Ct ◽

Bulk Properties ◽

Resolution Imaging ◽

Scan Data

Recent development of high resolution imaging modalities such as Micro-CT allow realistic porous structures to be straightforwardly and accurately scanned with sub-micron image resolutions possible on some commercially available systems. Combined with novel meshing techniques, these imaging techniques allow for robust and rapid conversion of the 3D scan data into finite element and finite volume meshes which can straightforwardly be used to characterize the response [1]. In addition, various image processing tools allow for interesting sensitivity analyses to be carried out helping to elucidate relationships between key architectural parameters, such as rib thickness, and bulk properties. A number of studies will be shown which demonstrate the ease with which fidelic models of the complex micro-architectures of bio-scaffolds can be generated.

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AN INVESTIGATION INTO THE FRICTIONAL PROPERTIES BETWEEN BONE AND VARIOUS ORTHOPEDIC IMPLANT SURFACES — IMPLANT STABILITY

Journal of Musculoskeletal Research ◽

10.1142/s0218957715500153 ◽

2015 ◽

Vol 18 (04) ◽

pp. 1550015 ◽

Cited By ~ 1

Author(s):

Jasan Dannaway ◽

Danè Dabirrahmani ◽

David Sonnabend ◽

Andrew Martin ◽

Richard Appleyard

Keyword(s):

Friction Coefficient ◽

Trabecular Bone ◽

Computer Modeling ◽

Normal Force ◽

Femoral Condyle ◽

Orthopedic Implants ◽

Micro Ct ◽

Testing Methods ◽

Friction Coefficients ◽

Frictional Properties

Background: The frictional properties between bone and uncemented orthopedic implants are important for initial stability. Accurate frictional data are used in computer modeling to improve implant design. Unfortunately, friction data derived from standardized testing methods is rare. We aimed to validate two testing methods and to provide friction data. Method: Two experimental designs for testing friction (Sled and Rotation) were investigated. One (Sled) employed a friction testing standard (ASTM D4518) while the other (Rotation) was a novel design. Both designs were initially validated using metal and polymer surfaces of known friction coefficients. The effect of variables, speed and normal force was evaluated. Finally trabecular bone from fresh frozen cadaveric femurs ([Formula: see text]) was tested against four commonly used orthopedic surfaces. Porosity of each bone sample was obtained using micro-CT and we reviewed the correlation between porosity and friction coefficient. Results: Based on the validation experiments, the Rotation method delivered more accurate friction estimates, and was less affected by normal force and speed, than the Sled method. The testing of bone against implant surfaces produced a variety of different force displacement curves and a wide range of friction coefficients (range 0.19–0.78). Bone excised from the lateral femoral condyle produced a higher friction coefficient than bone from the medial femoral condyle (p-value [Formula: see text]). Trabecular bone samples yielded a range of porosities (91.30–79.03%) as determined by micro-CT. A weak positive correlation was observed between bone porosity and friction coefficient. Conclusion: This study demonstrated the importance of a validated testing method when determining frictional properties between bone and orthopedic implants. Specific testing standards should therefore be created, to ensure accurate and reproducible data. The data produced in this study will be utilized for further experimental studies and computer modeling.

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