Analysis of the special features of hydrodynamics in the boundary layer of the nozzle of the developed surface

• Main Authors: Vladislav Shybetskуy, Serhii Kostyk
• Format: Article
• Language: English
• Published: PC Technology Center 2019-04-01
• Series: Tehnologìčnij Audit ta Rezervi Virobnictva
• Subjects: packed bioreactor; shear stress; computer simulation in the ansys environment; hydraulic resistance; flow shear rate
• Online Access: http://journals.uran.ua/tarp/article/view/165711
• ISSN: 2226-3780; 2312-8372

The object of research is the hydrodynamics of the boundary layer of the nozzle element of the proposed design. In the course of the study, computer simulation methods were used in the ANSYS environment, in particular the CFX block, which includes a set of physical, mathematical and numerical methods designed to calculate the characteristics of streaming processes. The analysis of the influence of the fluid velocity in the packed bed bioreactor on the magnitude of the hydraulic resistance for the following values of the fluid velocity: 0.1 m/s; 1 m/s; 2 m/s. The obtained data almost repeat the value of experimental studies, confirms the correctness of the construction of a computer model. A simulation of the hydrodynamics of a single nozzle of the proposed design for a longitudinal and transverse flow of fluid is done. Changes in the hydraulic resistance during transverse flow around the nozzle are insignificant, the maximum value lies within 101.3 kPa, for longitudinal washing the value of the pressure differential lies in the range from 98.96 to 102.7 kPa. Diagrams of the distribution of fields and velocity vectors in the boundary layer of the nozzle are obtained. When transversal washing of the nozzle, the magnitude of the velocities is in the range from 0 to 1.511 m/s, for longitudinal washer it ranges from 0 to 1.968 m/s. The distribution of the shear rate in the boundary layer is established, for the transverse washing of the nozzle, the magnitude of the shear flow rate ranges from 3.1 to 4.27·103 s-1, for a longitudinal washing of the nozzle, this indicator ranges from 5.6 to 1.25·104 s-1. Through the use of the proposed nozzle, it is possible to obtain large specific surface areas for the immobilization of microorganisms, provided that the critical parameters of the cultivation process are in accordance with permissible maximum deviations. Compared with the methods of determining the optimal parameters experimentally, a computer model is proposed that provides the following advantages: a significant reduction in the material costs of introducing a new nozzle design and a quick optimization of the process parameters when the initial data changes.