LiDong Huang, Principal Engineer, Experimental Research
Many different designs of plate heat exchangers (PHEs) exist for different heat transfer processes. Most PHEs are formed by corrugated plates, which are often spaced by rubber sealing gaskets or welded together to form hot and cold channels. Plate shapes and fluid distribution vary for different types of PHEs:
- Plate-and-frame heat exchangers (PFHEs)
PFHEs typically have rectangular plates with four corner ports, one pair for each of the two fluid streams. Gaskets are arranged so that the process and service fluids flow up or down alternate plates, as indicated in Figure 1. Hot and cold streams are typically in a cocurrent or countercurrent arrangement.
- Plate-and-shell heat exchangers (PSHEs)
PSHEs have circular plates with only two ports for plateside channels. The plates are welded on port edges to the adjacent plates to form shellside channels, as indicated in Figure 2. Shellside fluid is distributed through the annulus between the shell and plate pack. Different flow arrangements (e.g., cocurrent or cross flow) can be accomplished by changing nozzle locations on the shell.
- Welded plate heat exchangers (WPHEs)
WPHEs have rectangular or square plates that are welded on the edges alternatively to form cold and hot channels, as indicated in Figure 3. They are sometimes referred to as welded plate-and-block heat exchangers or fully welded plate exchangers. Unlike PFHEs, the two streams are typically in crossflow arrangement.
In the past, HTRI research and software of plate heat exchanger technology focused mostly on PFHEs. In an effort to improve our plate heat exchanger technology, HTRI initiated a multi-year technical program to conduct experimental and analytical research. We collaborated with plate heat exchanger manufacturers and collected significant amounts of liquid-phase and phase-change heat transfer and pressure drop data on three PSHEs (provided by Tranter, Inc. and Vahterus Oy) and one WPHE (provided by Hisaka Works, Ltd.).
In 2018, HTRI published two reports on PHE research. PHE-17-TR documents liquid-phase and flow boiling data in a WPHE provided by Hisaka Works, Ltd. This is the first time HTRI has collected boiling data and hydrocarbon condensation data in a WPHE. The data indicate that thermal and vapor-liquid stratifications are possible for horizontal flow in vertical channels. PHE-18-TR documents shellside flow boiling data in a PSHE provided by Vahterus Oy. Both reports also discuss using Xphe® to model PSHEs and WPHEs.
The data from the PSHEs and the WPHE, along with single- and phase-change data from other commercially available chevron-type corrugated plate heat exchangers (e.g., PFHEs), provide HTRI with a strong foundation for developing generalized heat transfer and pressure drop methods for corrugated crisscross channels and enhancing our software capabilities in the future.