Effect Of Taper Angle On Flow And Stress In Conical Shell Fluid Mixers

Abstract

Hollow cylindrical flow mixers achieve a homogeneous mixture with less pressure loss and higher momentum. However, the low volume of the mixer due to the hollow creates high pressure effects and mechanical stresses on the mixer. In this study, the stresses formed on the mixer by considering the flow and thermal effects of fluids in a conical cylinder mixer at different temperatures were examined. The effect of taper angle has been studied. In the examinations carried out using the finite element method, a verification study was first made, and solution sensitivity was determined. Water as fluid in standard conditions and common steel properties as cylinder material were used. Plate thickness was chosen to be 1 mm. It seems more appropriate to use a non-conical straight model to achieve thermal equilibrium. The taper angle reduced the velocity of fluid entering the mixer. Stress concentrations were observed at the supports and a lower and decreasing stress distribution was obtained for the conical mixer while it was constant for the straight cylinder in the other regions.

Keywords

• Cylindrical Mixer
• Taper Angle
• Von-Mises Stress
• Finite Element Analysis

Effect of Taper Angle on Flow and Stress in Conical Shell Fluid Mixers

Abstract

İçi boş silindirik akış karıştırıcıları daha az basınç kaybı ve daha yüksek momentum ile homojen bir karışım elde edilmesini sağlar. Bununla birlikte, oyuk nedeniyle karıştırıcının düşük hacmi karıştırıcı üzerinde yüksek basınç etkileri ve mekanik gerilmeler yaratır. Bu çalışmada, konik silindirli bir karıştırıcıda akışkanların farklı sıcaklıklarda akış ve ısıl etkileri dikkate alınarak karıştırıcı üzerinde oluşan gerilmeler incelenmiştir. Konik açının etkisi incelenmiştir. Sonlu elemanlar yöntemi kullanılarak yapılan incelemelerde öncelikle bir doğrulama çalışması yapılmış ve çözüm hassasiyeti belirlenmiştir. Standart koşullarda akışkan olarak su ve silindir malzemesi olarak yaygın çelik özellikleri kullanılmıştır. Levha kalınlığı 1 mm olarak seçilmiştir. Termal dengenin sağlanması için düz silindir şeklinde bir model kullanmak daha uygun görünmektedir. Konik açısı, miksere giren sıvının hızını düşürmektedir. Bağlantı yerlerinde gerilme yoğunlukları gözlenmiş ve diğer bölgelerde düz silindir için sabit iken konik karıştırıcıda daha düşük ve azalan bir gerilme dağılımı elde edilmiştir.

Keywords

• Silindirik Karıştırıcı
• Konik Açı
• Von-Mises Gerilmesi
• Sonlu Eleman Analizi

References

1. [1] Farbod A., Moghaddas J.S., Shokrgozar M. 2010. CFD simulation and experimental investigation of a jet mixer: effect of flow rate and jet angle on mixing time using the RSM model. 13th Iranian National Chemical Engineering Congress, 25-28 October, Kermanshah, Iran.
2. [2] Shuiping L., Xiaotian L., Lugang S. 2011. Simulation of the flow field of cement mixer based on numerical methods. Advances in Systems Science and Applications, 11 (3-4): 315-321.
3. [3] Kölbl A., Kraut M., Wenka A. 2011. Design parameter studies on cyclone type mixers. Chemical Engineering Journal, 167: 444–454.
4. [4] Jovanović A., Pezo M., Pezo L., Lević L. 2014. DEM/CFD analysis of granular flow in static mixers. Powder Technology, 266: 240–248.
5. [5] Meijer H.E.H., Singh M.K., Anderson P.D. 2012. On the performance of static mixers: a quantitative comparison. Progress in Polymer Science, 37 (10): 1333-1349.
6. [6] Akila R., Balu K. 2015. Regression model for fluid flow in a static mixer. Chemical Engineering Research Bulletin, 18: 23-29.
7. [7] Hanada T., Kuroda K., Takahashi, K. 2016. CFD geometrical optimization to improve mixing performance of axial mixer. Chemical Engineering Science, 144: 144–152.
8. [8] Pezo L., Pezo M., Jovanović A., Kosanić N., Petrović A., Lević L. 2016. Granular flow in static mixers by coupled dem/cfd approach. Hemijska Industrija, 70 (5): 539–546.

9. [9] Zhang C., Gu J., Qin H., Xu Q., Li W., Jia X., Zhang J. 2017. CFD analysis of flow pattern and power consumption for viscous fluids in in-line high shear mixers. Chemical Engineering Research and Design, 117: 190–204.
10. [10] Liu X., Hu Z., Wu W., Zhan J., Herz F., Specht E. 2017. DEM study on the surface mixing and whole mixing of granular materials in rotary drums. Powder Technology, 315: 438–444.
11. [11] Mihailova O., Mothersdale T., Rodgers T., Ren Z., Watson S., Lister V., Kowalski A. 2018. Optimisation of mixing performance of helical ribbon mixers for high throughput applications using computational fluid dynamics. Chemical Engineering Research and Design, 132: 942–953.
12. [12] Vega-Garcia D., Brito-Parada P.R., Cilliers J.J. 2018. Optimising small hydrocyclone design using 3d printing and cfd simulations. Chemical Engineering Journal, 350: 653–659.
13. [13] Vikash V.K. 2019. Turbulent statistics of flow fields using large eddy simulations in batch high shear mixers. Chemical Engineering Research and Design, 147: 561–569.
14. [14] Vikhansky A. 2020. CFD modelling of turbulent liquid–liquid dispersion in a static mixer. Chemical Engineering & Processing: Process Intensification, 149: 107840.
15. [15] Abotsi O.Y.W., Kizito J.P. 2020. Numerical study of heat transfer augmentation in an axially rotating pipe equipped with kenics mixer. Case Studies in Thermal Engineering, 21: 100695.
16. [16] Singh M.K., Anderson P.D., Meijer H.E.H. 2009. Understanding and optimizing the smx static mixer. Macromol. Rapid Commun., 30: 362–376.
17. [17] Jilisen R.T.M., Bloemen P.R., Speetjens M.F.M., Three-dimensional flow measurements in a static mixer, AIChE Journal, 59(5), 1746-1761, 2013.
18. [18] Ugwu C.U., Ogbonna J.C., Tanaka H. 2002. Improvement of mass transfer characteristics and productivities of inclined tubular photobioreactors by installation of internal static mixers. Appl Microbiol Biotechnol, 58: 600–607.
19. [19] Shah L.J., Furbo S. 2003. Entrance effects in solar storage tanks. Solar Energy, 75: 337–348.
20. [20] Ansari M.A., Qamareen A., Ansari M.Z. 2019. Mixing of fluids in vortex t-mixer with two and four nonaligned inlet microchannels. IOP Conf. Series: Materials Science and Engineering, 691: 012030.
21. [21] Sheu T.S., Chen S.J., Chen J.J. 2012. Mixing of a split and recombine micromixer with tapered curved microchannels. Chemical Engineering Science, 71: 321–332.
22. [22] Nimafar M., Viktorov V., Martinelli M. 2012. Experimental comparative mixing performance of passive micromixers with h-shaped sub-channels. Chemical Engineering Science, 76: 37–44.
23. [23] Miyoshi K., Kamaya M., Utanohara Y., Nakamura A. 2016. An investigation of thermal stress characteristics by wall temperature measurements at a mixing tee. Nuclear Engineering and Design, 298: 109–120.
24. [24] Utanohara Y., Nakamura A., Miyoshi K., Kasahara N. 2016. Numerical simulation of long-period fluid temperature fluctuation at a mixing tee for the thermal fatigue problem. Nuclear Engineering and Design, 305: 639–652.
25. [25] Ansari M.A., Kim K., Anwar K., Kim S.M. 2012. Vortex micro t-mixer with non-aligned inputs. Chemical Engineering Journal, 181– 182: 846–850.
26. [26] Versteeg H.K., Malalasekera, W. 2007. An introduction to computational fluid dynamics, 2nd edition. Pearson Education Limited.
27. [27] White F.M. 2016. Fluid mechanics 8th edition, McGraw Hill.
28. [28] Budynas R., Nisbett K. 2020. Shigley's mechanical engineering design 11th edition, McGraw Hill.
29. [29] Baldyga J., Pohorecki R. 1995. Turbulent micro mixing in chemical reactors – a review. Chem. Eng. J., 58(2): 183–195.
30. [30] Bourne J.R. 2003. Mixing and the selectivity of chemical reactions. Org. Process Res. Dev., 7(4): 471–508.
31. [31] Gradl J., Peukert W., Characterization of micro mixing for precipitation of nanoparticles in a t-mixer, 105-124, Micro and Macro Mixing, Analysis, Simulation and Numerical Calculation, Springer, 2010.
32. [32] Ghanem A., Lemenand T., Valle D.D., Peerhossaini H. 2014. Static mixers: mechanisms, applications, and characterization methods a review. Chemical Engineering Research and Design, 92: 205–228.