THE EFFECT OF THERMOPHYSIZAL PROPERTIES OF FLUIDS ON CONVECTIVE HEAT TRANSFER IN ELECTRONIC DEVICES

The impact of enclosure aspect ratio and different thermophysical properties of fluids on heat transfer were investigated in rectangular enclosure with 3x3 array of flush-mounted chips placed on the front vertical wall with constant temperature and cooled by the opposite wall. To study heat transfer inside the enclosure simulations were done for four enclosure aspect ratios(A=1.0, 5.0, 7.5, 20.0) and five fluids(air, water, FC-40, FC-72, FC-88). Numerical results show that the highest velocities are in the air while low velocities have been noticed in the water, FC-40, FC-72, FC-88. The maximum air velocities for the W component are obtained precisely at a height of Z= 5.5. It is observed that when enclosure aspect ratio decreases, the fluid velocity increases. Maximum Nu number was when enclosure was filled with dielectric fluids FC-72 and FC-88, and minimal was found in the air. To ensure that chosen numerical methods, computer program was implemented correctly test task were completed. Good agreement is found between the results.