mixed convection in ventilated enclosure
- 1. 1 MIXED CONVECTION IN VENTILATED ENCLOSURES SEMINAR 02-02-2016 YOOSAF PP (REG. NO:B2ENME2761) Under the guidance of Dr ABOOBACKER KADENGAL
- 2. OVERVIEW 2 • Introduction. • Mixed convection. • Types of mixed convection. • Importance of mixed convection. • Applications. • Conclusions.
- 3. INTRODUCTION • Conduction. • Convection. Natural convection. Forced convection. • Radiation. What you mean by conjugate heat transfer? Have you heard about the term “Mixed convection”?
- 4. WHAT IS MIXED CONVECTION??? Mixed convection occurs if the effect of buoyancy forces on a forced flow or the effect of forced flow on a buoyant flow is significant. The governing non-dimensional parameters for the description of flow is Grashof number (Gr), Reynolds number (Re) and Prandtl number (Pr).
- 6. CHARACTERISTICS OF DIMENSIONLESS NUMBERS??? Analysis indicates that Richardson number (Ri) characterizes mixed convection flow where Gr and Re represent the strength of the natural and forced convection flow effects, respectively. The limiting case Ri→0 and Ri→∞ correspond to the forced and natural convection flows, respectively.
- 7. WHAT ARE THE TYPES OF MIXED CONVECTION? 1.ASSISTING MIXED CONVECTION The forced flow can be in the same direction as the flow created by natural convection, and this flow condition is called assisting mixed convection.
- 8. 2.OPPOSING MIXED CONVECTION Forced flow direction is in an opposing direction to the flow that is created by buoyancy, and this flow condition is referred to as opposing mixed convection.
- 9. 3.TRANSVERSE MIXED CONVECTION Convection from a horizontal heated enclosure, the forced flow is perpendicular to the buoyancy induced flow and this situation is called transverse mixed convection.
- 10. WHY MIXED CONVECTION NEEDED??? In an enclosure, the interaction between the external forced stream and the buoyancy driven flow will result a increased high heat flux from electronic modules leads to the possibility of complex flows. Accurate flow analysis for precise heating and cooling application.
- 11. FLOW REGIMES
- 12. FLOW REGIMES
- 13. VENTILATION METHODS??? 1. Mixing (dilution) ventilation : Mixed flow air is delivered into a ventilated space by turbulent air jets. 2. Displacement ventilation :Low velocity air supply into an occupied zone.
- 14. WHAT IS DOUBLE-DIFFUSIVE MIXED CONVECTION??? Kinds of convection involved in a ventilated room. Double diffusive convection is a fluid dynamics phenomenon that describes a form of convection driven by two different density gradients, which have different rates of diffusion.
- 15. WHERE MIXED CONVECTION USES ??? Mixed convection occurs in many heat transfer devices, such as the cooling system of a nuclear power plant, large heat exchangers, cooling of electronic equipment, ventilation and pollution agent clearance.
- 18. THANK YOU