• Mechanics, Semester 3, position 2

In the field of multiphase flows, important engineering problems are particularly studied, such as: fluidization, pneumatic transport, hydraulic transport, pneumatic-hydraulic lifts, cavitation, evaporation, condensation and biphasic flows. skills that treat the problems of one-dimensional multiphase flows in pipes and ducts.

The student has knowledge in the field of multiphase flows - mixtures of fluids and solids, or mixtures of different fluids. He knows and knows that he uses: characteristic particle shapes, various forms of volume and mass concentration, physical properties of mixtures, deposition rate, critical fluid velocity, and characteristic current magnitudes of one-dimensional flows. The basic outcomes of the course are to learn and master calculation skills for different classes of incompressible and compressible multiphase flows that take place without or with heat exchange, such as: application of appropriate design models that provide basic engineering current parameters: pressure, flow rate, flow rate and pressure drop in pipes and ducts at specific flows: in fluidized beds, hydraulic and pneumatic transport, and pneumo-hydraulic lift. Using the knowledge gained, the student is able to dimension the pipeline system for transporting mixtures. An important part of learning outcomes is learning about different modes of transport, selecting and calculating separators.

The concept and types of mixtures and properties of mixtures.Basic equations for calculating the flow of mixtures. Laws of maintaining matter, quantities of motion and energy, equation of diffusion, equation of motion of particles. Eulerian and Lagrangian approaches to the study of multiphase flows. One-dimensional multiphase flow equations in pipes. Forces acting on gas bubble and solid particle, Stokes solution. Concentrations. MULTIPHASE FLUID AND SOLID PARTICLE FLOWS: Deposition velocities. Porosity. Pressure drop in fluidized bed. Calculation of pressure change in isothermal compressible flow. The first and second critical fluidization velocities. PNEUMATIC TRANSPORT. Application, Advantages and Disadvantages, and Pneumatic Transport Systems. Horizontal pneumatic transport. Fluid lift. FLYING PNEUMATIC TRANSPORT. Isothermal compressible streams of the mixture. Critical Stream Speed. HYDRAULIC TRANSPORT. Suspension rheology. Laminar suspension flow. .Hydraulic transport of inhomogeneous mixture in horizontal, vertical and oblique pipelines. Application and calculation of pneumo-hydraulic lift. TWO-PHASE FLOW. Flow modes and maps in horizontal and vertical tubes. Determination of pressure drop. Lockart-Martineli method. Hydraulic characteristic of the mixture. Two-phase streams with separation surface. Cavitation, evaporation, condensation. Two-phase flows in heat exchange tubes. Numerical methods for multiphase flow calculation.

TRANSPORTATION OF MIXTURES. Particle shape. Form factor. Equivalent particle. The force of resistance. Resistance coefficient. Mass concentration measurement. FLUIDIZATION. The movement of a particle through a fluidized bed. Porosity of fluidized bed. PNEUMATIC TRANSPORT. Change in pressure in an incompressible and compressible fluidized bed as a function of supplementary resistance. FLYING PNEUMATIC TRANSPORT. Pneumatic transport systems. Vacuum cleaners. Dispensers. SEPARATION. Degree of separation. Selection criteria for separator type. Solid material separation chambers. Canvas and electrostatic filters. Cyclones. HYDRAULIC TRANSPORT. Application, division, critical fluid velocity and viscosity of the homogeneous mixture. Hydraulic transport systems. EJECTORS. Application, ejector characteristics. Determination of optimal ejector parameters.

Regular attendance. Preferably, the student has previously taken a course in Fluid Mechanics M.

Chair Book and Collection (in the library). Laboratory equipment and installations.

Total assigned hours: 75

New material: 20
Elaboration and examples (recapitulation): 10

Auditory exercises: 26
Laboratory exercises: 4
Calculation tasks: 0
Seminar paper: 0
Project: 0
Consultations: 0
Discussion/workshop: 0
Research study work: 0

Review and grading of calculation tasks: 0
Review and grading of lab reports: 2
Review and grading of seminar papers: 0
Review and grading of the project: 0
Test: 8
Test: 0
Final exam: 5

Activity during lectures: 5
Test/test: 35
Laboratory practice: 5
Calculation tasks: 0
Seminar paper: 0
Project: 0
Final exam: 55
Requirement for taking the exam (required number of points): 10

Crnojević C., Transport of solid materials through pipes, Faculty of Mechanical Engineering, Belgrade, 2002. (in Serbian); Šašić M., Transport of fluids and solid materials through pipes. Scientific book, Belgrade, 1990. (in Serbian); Šašić M., Calculation of the transport of fluids and solid materials through pipes. Scientific book, Belgrade, 1985. (in Serbian)