Abstract: Two typical internal flow patterns are chosen to carry out the internal heat transfer experiments based onthe fronter fluid flow characteristics. By changing the height and type of the pin-fins, the internal heat transfer onthe boards can be learned. The heat transfer coefficients decrease when increasing jet spacing and the distance fromthe jet to the target . The square shaped pin fins produce the highest internal heat transfer, followed by diamond andcircular pins. The variation of the height of the channel has effects on the fluid flow, and shows different heat transfer coefficient distributions. The Nusselt number based on the length scale of the ratio internal volume to heat transfer surface increases with the impingement Reynolds number. Nusselt number is shown to be linear on a log-log scalewith Reynolds number.

Key words: lamilloy, pin-fins, internal surface, heat transfer characteristics