This work describes numerical modelling of underground hydrocarbon storage tank dip gauge. The work was carried out at the request of a petroleum company faced with predicament, whereby three underground tanks, for the storage of hydrocarbon products, namely, Petroleum Motor Spirits, Automotive Gas Oil, and Dual Purpose Kerosene, were fully installed and buried in the earth without provision for the fluid measuring gauge. The objective was to design and fabricate a dip gauge with the design capacity of measuring up to 30,000 L of hydrocarbon from the underground storage tank. To achieve the objective of designing an accurate and reliable gauge, mathematical analysis of the available data of tanks was carried out using Newton-Raphson iteration method. A model dip gauge was designed and calibrated with the results of mathematical analysis. The dip gauge was designed with measurement capability between the range of 200-15,886 L and 400-31,765 L of hydrocarbon in the smaller and bigger tanks, respectively. Aluminium alloy 6063-T6 was used for fabrication of the gauge on account of its excellent strength and good corrosion resistance in relevant hydrocarbon environment.
