Transient experimental investigation of micro heat pipes

An experimental investigation was conducted on several small, tapered micro heat pipes specifically designed for use in the thermal control of ceramic chip carriers to verify the operation, measure the performance limits and transient behavior, and determine the accuracy of a previously developed numerical model. Several heat pipes were evaluated for transient conditions, i.e., startup or rapid changes in the thermal load. The experimental data are compared with the results of a previously developed analytical model to determine the accuracy of the model and verify the predicted trends. The experimental results indicated that the transient numerical model is capable of accurately predicting the maximum transport capacity prior to the onset of dry out, the temperature distribution throughout the longitudinal position, and the temperature difference between axial locations on the heat pipe to within 0.3°C. Although the numerical model was found to accurately predict the steady-state behavior, the numerical model substantially underestimated the transient response.