Simulation Analysis of Verification Results of Fuel Dispenser Metal Measuring Vessel under Different Temperature Conditions

Field verification of fuel dispensers usually adopts 20 L and 50 L metal measuring vessels as working standards. Thermal expansion of thin-wall stainless steel vessels under varying temperatures changes the volume corresponding to scale marks, and environmental temperature fluctuations are converted into indication errors. Based on the physical prototype and key dimensions of 20 L and 50 L measuring vessels, a three-dimensional parametric model of 304 stainless steel is established in this paper. Temperature working conditions are set at 5 ℃ intervals within the range from 0～40 ℃. The thermal-structural sequential coupling finite element method is applied to calculate temperature field, thermal deformation and volume drift, and volume deviation is equivalently transferred to verification error. The results show that the volume of both measuring vessels varies approximately linearly with temperature under a uniform temperature field. The volume sensitivity of the 20 L vessel is about 1.02 mL/℃, and that of the 50 L vessel is about 2.55 mL/℃. When the temperature rises from 20～40 ℃, the volumes increase by approximately 20.4 mL and 51.0 mL respectively. Judging results according to the nominal volume at 20 ℃ will introduce a systematic deviation of about 0.102 %. After considering three-point support constraints and the heat transfer difference between the top and side wall, a non-uniform temperature field with displacement gradient appears in the transition zone, which causes an extra volume deviation of 0.2～3.1 mL at the same ambient temperature. A two-point temperature measurement equivalent temperature correction model is proposed according to the contribution of sensitive zones. This model can reduce the additional deviation to the milliliter level and provides operable quantitative reference for on-site temperature control, temperature measuring point layout and measuring vessel correction.