Manipulating heat-transfer coefficient

Hi All,

I have 3 domains, from bottom to top iron, air and glas. Iron and Glas are defined as heat transfer in solid, Air as heat transfer in fluids. Iron being heated, the heat flow to air and glas.

i want to increase the heat flux from iron to air by manipulating the heat-transfer coefficient.

the convective cooling doesnt work here, it works only at outer boundary.

thanks. happy weekend

akmal