RTC Update: Modifications of Test Rigs Lead to Software Improvements

David Burton, Director, Research & Technology Center

HTRI software is rooted in our research. We use information gathered to develop and improve our software products, which users consider the world’s most accurate for design and simulation of heat transfer equipment. Modifying our test rigs helps us learn more about design, prediction, and modeling processes, leading directly to improvements in our software.

A new serpentine flow loop was constructed for visualization and collection of pressure drop measurements for developing two-phase flow phenomena inside pipe geometry. Experimental results will help us improve modeling of piping pressure losses in our fired heater software, Xfh® and Xfh Ultra.

The serpentine flow loop allows simulation of two-phase flow phenomena inside fired heater piping.

We are currently testing shellside condensation in a vacuum using the Low Pressure Condensation Unit (LPCU). Testing is near completion with a plain tube bundle. We will begin testing a low-finned tube bundle soon. The shellside test section includes sight glasses for visual observations. Condensation of immiscible mixtures of water and hydrocarbons are also being studied in the shellside vacuum condenser. Using our test results, we can develop condensation methods that allow Xist® users to design condensers using immiscible mixtures.

With the shellside test section in the LPCU, HTRI collects data with multiple tube designs and various fluids, including immiscible mixtures.

Testing for instabilities and turndown limits in a vertical thermosiphon reboiler has been our continued focus for the Prototype Test Unit (PTU). One objective of this study is developing recommended exchanger performance criteria to avoid instabilities. Initial experimental data have been compared with Xist circulation calculations and piping pressure drop predictions to help reduce tubeside pressure loss.

We just completed experimental research with a falling film evaporator installed on the Multipurpose Boiling Unit (MBU). Using the collected data, we plan to develop correlations that improve the accuracy of pressure drop and heat transfer predicted by Xist for falling film evaporators.

A new air cooled heat exchanger (ACHE) is currently being fabricated, with delivery and installation expected this month. Using this unit, we can compare detailed airside distribution measurements with CFD models. With two fan cells, our ACHE will be configurable for forced, induced, or natural draft operation.

HTRI software tools, backed by ongoing research results, are highly flexible and effective. Research and experimental testing at our RTC ensures that HTRI provides the most accurate predictions of exchanger performance available.