Heat flux with oscillating heat sink

[tempneff]

I am curious about the effects of oscillation in a heat transfer system. For example consider a simple system consisting of a heat source, a heat sink, and some generic material through which we will flow heat.

http://tempneff.com/Hflux.png

If we stack them all together, without thermal grease or other treatments, then they should transfer heat by $\frac{Q}{t}=\frac{\kappa A(T_{hot}-T_{cold})}{d}$

where Q= heat transferred, t=time, $\kappa$ = thermal conductivity of barrier, A = area, T= temp, and d=thickness of barrier. Right?

What would be the effect if I were to vibrate the cold side? Instinctively I thought it would interrupt heat flow decreasing Q/t, but I am reading (unless I misunderstand) that sometimes heat transfer is improved by oscillation.

Any thought?

 

[Seth.T]

If i understand you correctly, I think the logic is similar to having a fan blowing to the heatsink on the other end, decreases Q/t because it increases heat dispersion thus improves natural convection on the outer surface, therefore improve Heat flux to surrounding.

 

[tempneff]

I'll buy that. I still wonder about the magnitude of effect from other dynamics. At high frequency would the friction created have a noticeable effect on the net flux? What about the change in surface area when part of the cold block is shifted off of the 'material'?

 

[Seth.T]

Higher frequency means more oscillation, so its similar to a higher RPM fan which gives better cooling measure..

 

[sardar]

I can provide some insight into the concept of heat flux with an oscillating heat sink. First, let's define heat flux as the rate of heat transfer per unit area. In the example given, the heat source and heat sink are connected by a material with a certain thermal conductivity, and the heat flux is determined by the temperature difference between the hot and cold sides.

When the cold side is oscillated, it can have both positive and negative effects on heat transfer. On one hand, the oscillation can disrupt the boundary layer of the material, allowing for more efficient heat transfer. This is known as "forced convection" and is commonly used in cooling systems for electronic devices.

On the other hand, if the oscillation frequency is too high, it can create a layer of stagnant air on the cold side, which can act as an insulator and decrease heat transfer. This is known as "thermal resistance" and can be detrimental to heat transfer.

In order to fully understand the effects of oscillation on heat transfer, it is important to consider the specific conditions of the system, such as the material properties, oscillation frequency, and temperature difference. Conducting experiments and simulations can help determine the optimal conditions for heat transfer in an oscillating heat sink system.

In summary, oscillation can have both positive and negative effects on heat transfer, and it is important to carefully consider the specific conditions in order to optimize heat flux in a system.