SIMPLE algorithm was used to simulate natural convection in a cylinder with an internal slotted annulus under different slotted structures

the influence on the heat transfer and fluid flow was studied when changing slotted degree and radius ratio. The results showed that under the same conditions calculated numerical results were in good agreement with the existing experimental results. The slot can enhance the heat transfer

but not slotted degree the greater the better. Radius ratio influenced on the heat transfer

showing that the radius ratio was smaller

the annular space more narrow

so the heat transfer effect was worse. With the increase of the radius ratio

the Keq increased obviously

but when the radius ratio exceeded 2

the Keq remained the same.