Interrelation between pin length and heat exchanger performance

• No optimal pin length can be identified based common pin performance parameters.
• Modified pin performance parameters are recommended.
• Optimal pin lengths for different flow conditions and pin arrangement are derived.
• Highest heat exchanger performance corresponds with optimized pin length.

One of parameters influencing pin performance in a heat exchanger is pin length. The optimization of these parameters usually is carried out by considering pin as single heat transfer element operating under some ideal conditions. Optimal pin performance parameters derived in such analysis might not result in optimal heat exchangers. Current paper focuses in such inconsistencies and proposes a novel approach to be followed by optimization of pin length of a practical heat exchanger. The approach proposed in current paper consist in introducing of a corrected pin length in order to consider the influence of channel height carrying fluid on the opposite site to the heat exchanger channels employing pin fins. In the paper is demonstrated that by following the proposed approach one can derive optimal pin length to pin diameter ratios which results in optimal pin performance figures respectively in optimal performance of entire heat exchangers. The approach proposed here, in principle may be used to optimize other fins of other forms commonly used in flat plate and fin heat exchangers.