Accurate Heat Transfer Coefficient Research Articles

Evaluation of Temperature and Heat Transfer Conditions at the Metal-Forming Interface

This work is part of an on-going study of the physics of the die-workpiece interface in metal forming. An experimental investigation has been conducted on the temperatures at the interface in metal forming. This work differs from others in that the temperatures are measured directly at the die-workpiece interface. The raison d'etre for this work is the experimental data from these measurements can be used to derive accurate heat transfer coefficients (thermal resistances). For the experiments in this work two flat platens were used as dies with both hot and cold solid cylinderical billets. The results indicate that this method can provide a reliable means of predicting the contact resistance.

Inverted annular flow boiling

The convective heat-transfer coefficients of inverted annular flow film boiling in the region immediately downstream of the rewetting front in the bottom flooding mode were calculated and were found to agree very well with the experimental values. Also, the results of the analysis reconfirmed that having more accurate heat-transfer coefficients in a confined space immediately downstream of the rewetting front substantially improves the accuracy of the estimate for rewetting velocities.

Measurement of Convective Heat Transfer Coefficients During Food Freezing Processes

ABSTRACTAny prediction of freezing time for a food product depends on accurate heat transfer coefficients. The purpose of this investigation was to examine experimental procedures for accurate determination of convective transfer coefficients during freezing of food products. Measurements of heat transfer coefficients during cooling of any acrylic transducer and ground beef with similar size and shape were conducted at air temperatures below initial freezing point of the product. The results indicate that accurate measurements of the coefficients can be achieved through nonlinear regression analysis of temperature histories within an acrylic transducer.