Multiphase flow and heat transfer Lesson 1 Po Hu NSSE-SJTU
Multiphase flow and heat transfer Lesson 1 Po Hu NSSE-SJTU
Introduction Multiphase flow covers a vast field,cross different scales,different engineering disciplines,different application contexts,and different analytic approaches. Therefore one course for the fundamental understanding of,a unifying approach to the multiphase flow
Introduction • Multiphase flow covers a vast field, cross different scales, different engineering disciplines, different application contexts, and different analytic approaches. • Therefore one course for the fundamental understanding of , a unifying approach to the multiphase flow
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Phase Phase refer to liquid,solid,and vapor state of material 。 Multiphase flow means a flow of a mixture of phases,ignoring the well mixed flow above the molecular level ·Classification: state of different phase:solid-gas flow Application slurry flow,aerosols A specific type:low Reynold suspension flow Multiphase flow phenomena is everywhere: Industrial application - Nature world,biological and medical fluid Dispersed phase flow and separated phase flow Dispersed phase flow means one continuous phase containing a discrete phase,such as rain droplet in air. Separated phase flow means two phases are separated by a well-defined surface(interface), such as river surface. In a separated phase flow,one can travel from one point to another in/through the same phase
Phase • Phase refer to liquid, solid,and vapor state of material • Multiphase flow means a flow of a mixture of phases, ignoring the well mixed flow above the molecular level • Classification : – state of different phase: solid-gas flow – Application :slurry flow, aerosols – A specific type: low Reynold suspension flow • Multiphase flow phenomena is everywhere: – Industrial application – Nature world, biological and medical fluid • Dispersed phase flow and separated phase flow – Dispersed phase flow means one continuous phase containing a discrete phase, such as rain droplet in air. – Separated phase flow means two phases are separated by a well-defined surface(interface), such as river surface. – In a separated phase flow, one can travel from one point to another in/through the same phase
Examples ·Gas-liquid flow Droplet in gas or bubble in liquid -Atomization for small droplet for combustion Steam-water flow in power plant Flow pattern includes bubble flow to annular flow Gas-solid flow - Gas with suspended solid particles,such as granular flow where particle- particle and particle-wall interaction is much more important than the forces due to the interstitial gas particle is motionless,then the gas flows through porous medium,the viscous force is the dominant force between gas-particle,such as pebble-bed heat exchanger. 一 Fluidized bed Cyclone separator 一 Combustion of coal in power plant Solid-propellant rocket exhausts
Examples • Gas-liquid flow – Droplet in gas or bubble in liquid – Atomization for small droplet for combustion – Steam-water flow in power plant – Flow pattern includes bubble flow to annular flow • Gas-solid flow – Gas with suspended solid particles , such as granular flow where particleparticle and particle-wall interaction is much more important than the forces due to the interstitial gas – particle is motionless, then the gas flows through porous medium, the viscous force is the dominant force between gas-particle, such as pebble-bed heat exchanger. – Fluidized bed – Cyclone separator – Combustion of coal in power plant – Solid-propellant rocket exhausts
Examples Liquid-solid flow,slurry flow Transport of coals and ores,flow of mud Flow through solid,porous media flow 。Three phase flow -Particle-fluid-bubble flow,such as bubble in slurry flow Less studied The multiphase flow mostly refers to 'various types of two-phase flow
Examples • Liquid-solid flow, slurry flow – Transport of coals and ores, flow of mud – Flow through solid, porous media flow • Three phase flow – Particle-fluid-bubble flow, such as bubble in slurry flow – Less studied • The multiphase flow mostly refers to ‘various types of two-phase flow’
A topic list 1. Gas-liquid 2. Boiling and condensation 3.Pneumatic transport and slurry transport 4. Fluidized bed 5.Flow of aerosol particles 6.Removal of dust and droplet from gas steams 7.spray 8.Granular flow 9.Porous media flow 10.Multiphase flow in microgravity and micro-scale dimentions 11.Basic multiphase interactions 12.Numerical modeling 13.Measuring instrumentation
A topic list 1. Gas-liquid 2. Boiling and condensation 3. Pneumatic transport and slurry transport 4. Fluidized bed 5. Flow of aerosol particles 6. Removal of dust and droplet from gas steams 7. spray 8. Granular flow 9. Porous media flow 10. Multiphase flow in microgravity and micro-scale dimentions 11. Basic multiphase interactions 12. Numerical modeling 13. Measuring instrumentation
Multiphase flow model Three ways to establish a model in fluid mechanics -Experiment with lab instruments (limit on facility size) -Theory with mathematical equation (limit on Complexity) Computation with computer(limits on computing power) Simplification needed for modeling
Multiphase flow model • Three ways to establish a model in fluid mechanics – Experiment with lab instruments (limit on facility size) – Theory with mathematical equation (limit on Complexity) – Computation with computer (limits on computing power) • Simplification needed for modeling
