Week 6: Conjugate Heat Transfer Simulation

AIM: To perform a Conjugate heat transfer simulation through a pipe.

THEORY:

The term conjugate heat transfer (CHT) is used to describe processes that involve variations of temperature within solids and fluids, due to thermal interaction between the solids and fluids. Conjugate heat transfer corresponds with the combination of heat transfer in solids and heat transfer in fluids. In solids, conduction often dominates whereas, in fluids, convection usually dominates. Efficiently combining heat transfer in fluids and solids is the key to designing effective coolers, heaters, or heat exchangers. Forced convection is the most common way to achieve a high heat transfer rate. In some applications, the performances are further improved by combining convection with phase change (for example liquid water to vapor phase change). Heat transfer in solids and heat transfer in fluids are combined in the majority of applications. This is because fluids flow around solids or between solid walls and because solids are usually immersed in a fluid.

PROCEDURE: 

• Initially the cylinder geometry is created in converge studio and the boundary flagging is done.

• Now we begin with the case setup.

setup:

• Materials

1. Gas simulation - Air
2. solid simulation - aluminium

     3.species - O2 and N2

• Simulation parameters

1. run parameters

     2.Simulation time parameters

• boundary

        inlet velocity should be calculated with the given reynolds number.

        Re = 7000, rho = 1.1766 kg/m3 , dynamic viscosity = 0.00001846 kg/ms , D = 0.03m

         `Re = (rho*v*D)/mu`

           `v=(Re*mu)/(rho*D)`

              by substituting the above values we get velocity as v = 3.66m/s

• Regions and initialisation

fluid region

solid region

super cycle model

• Grid size - 0.004m

Results:

case-1: mesh size = 0.004m

mesh

temperature

velocity

idreg

Y+

temperature plot for fluid region:

temperature plot for solid region:

total cells:

case-2: mesh size = 0.003m

mesh:

temperature:

velocity:

idreg:

Y+

temperature plot for fluid region:

temperature plot for solid region:

total cells:

case-3:mesh size = 0.002m

mesh

temperature

idreg

velocity

Y+

temperature plot for fluid region:

temperature plot for solid region:

cells

temperature animation:

Conclusion:

As the mesh is refined i.e. size is reduced, the no.of cells increases an also the obtained values are more accurate.

The CHT simulation is carried out successfully using converge.