MODULE 3

Section 1:   

Boundary Layer and Turbulence

Section 2:   

Pressure Drop and Friction Factor

Section 4: 

Convection With Change of Phase

Correlations for Heat Transfer Coefficient

The correlations for h are normally established in dimensionless form as a function of the Reynolds (for forced convection) and the Grashof number (for natural convection):

(3.20)

where:

In the above dimensionless numbers x is a characteristic length and for internal flows x is generally replaced by the equivalent diameter.

In most reactors the cooling of fuel elements, vessel and other elements is made through turbulent forced convection. A wide variety of coolants are used depending on the reactor type. For example, pressurized water reactors (PWRs) use de-mineralized water, fast reactors use molten metals (such as liquid sodium) and natural uranium fuel reactors use heavy water.

Considering the most used coolants in nuclear reactors there are two groups of turbulent forced convection correlations of interest:

a) Fluids with high Pr (gases, water)

 Previous page

 Next page

3/5