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A typical problem faced by process and safety engineers is calculating the wetted area of tanks and vessels — for example, when determining the required relief load for a fire case. This area is the sum of the wetted areas of the unit’s parts, which may consist of shells and heads of different types. Of course, numerical integration can provide the answer. However, having exact or accurate approximate analytical formulas allows an engineer to do this calculation quickly and simply by hand or in a spreadsheet.
Several authors [1–5] have investigated and reviewed this subject; appropriate formulas are known for many types of shells/heads. However, three types of heads — side elliptical, dished and torispherical — have lacked proper equations. Unfortunately, these types of heads are used very often.
This article solves that problem, proposing general exact or accurate approximate equations for wetted area for those three types of side heads.
LEONID KORELSTEIN is vice president of research and development for Piping Systems Research and Engineering Co., Moscow. Email him at [email protected].
ACKNOWLEDGEMENTS
The author thanks: Nikolai Maximenko for help with the illustrations; Valery Osipov for fruitful cooperation during work on derivation of these formulas; Elena Yudovina and Alexey Timoshkin for ongoing support and productive discussions during this project; Georges Melhem, who inspired the author to engage in this endeavor; and all friends and colleagues at Piping Systems Research and Engineering and the Design Institute for Emergency Relief Systems for their interest and support.
REFERENCES
1. “SuperChems Technical Reference,” Chapter 3.3 — Detailed Volume Equations, ioMosaic, Salem, N.H. (2010).
2. Lutus, P., “Storage Container Mathematics,” p. 15, (2014).
3. Jones, D. E., “Find Tank Wetted Surface Area,” Chemical Processing, 80 (2), p. 21 (Feb. 2018).
4. Jones, D. E., “Calculating Tank Wetted Area,” ChemicalProcessing.com, (2017).
5. “Calculate Surface Areas and Cross-sectional Areas in Vessels with Dished Heads,” White Paper WP-14-03, Honeywell, Houston (2014).
6. Doane, R. C., “Accurate Wetted Areas for Partially Filled Vessels,” Chem. Eng.,114 (9), p. 56 (Sept. 2007).
