Q1-9 IST Incremental Delta Correction Method
Many researchers have observed the effect of temperature profile distortion on the mean temperature driving force in shell-and-tube heat exchangers. A. Salehpour, J. W. Palen, and R. S. Kistler study the mechanism of temperature distortion and developed a theoretical method to evaluate and adjust the distortion to obtain the true mean temperature difference (MTD). HTRI implemented this method, known as the delta correction method, in ST. Extensive testing has proved that this method is valid and necessary to predict HTRI research data.
The delta correction method was originally developed as an overall calculation procedure treating the whole shell-and-tube exchanger as one increment. However, IST applies a three-dimensional grid over the exchanger; each tubepass, baffle spacing, baffle window, and cross flow is located in a different increment. Also, the calculation engine is fully localized. All these conditions make directly adopting ST’s overall delta correction method impossible. Thus, an incremental delta correction method had to be developed for IST.