The purpose of a heat exchanger header box is to act as a high pressure manifold that redistributes process
fluid from a central source to a bundle of finned tubes where it can be cooled. Due to the lack of certified
cover type header box design codes, industrial manufactures are left to develop their own in-house codes.
This paper presents an investigation of an in-house design code and compares its results with those from
finite element analyses. After analysing multiple sample designs, it was found that header boxes designed
using this method were all over-designed. To address this problem, a new 2D finite element software package
was developed, based on an open source platform, and validated to accurately analyse cover type header boxes.
The software can be used to validate any existing designs, as well as to provide an optimal design and accurate
stress predictions for new header boxes, thus reducing uncertainty in the design process. The focus of this research is to investigate and improve the methods used to design cover type header boxes
for aircooled heat exchangers. An air-cooled heat exchanger is a device that rejects heat from a process fluid
directly to ambient air. By construction, it is a vessel that removes heat from a process fluid by forcing cool
ambient air over a collection of finned tubes through which the fluid is flowing. Figure 1 shows a typical layout of an induced draft air-cooled heat exchanger. Hot process fluid is pumped into an inlet header box, which channels the fluid into the finned tubes. Here the fluid flows through the tubes and into an outlet header box before exiting through an outlet nozzle. Simultaneously, cool air is blown over the finned tube bundle by a fan to accelerate the exchange of heat between
the air and the fluid in the tubes. The purpose of the heat exchanger header box is to act as a manifold.
For the header box shown in figure 2, process fluid will flow into the two large nozzles and out
through the holes in the tube sheet. The two most commonly used header box design