(140a) Affinity Law Deviations in High Pressure Lng Pump Performance

Liquefied natural gas pumps are subject to the affinity laws and divergence from an affinity law surface fit is common. According to American Petroleum Institute (API) Standard 610, deviations are measured from the tested data point to the surface fit curve only in the vertical direction. However, as suggested by Hjorth et al (2006) and Pauly et al (2002), the true deviations of a tested point to the surface fit curve occur in both the vertical and horizontal directions, thereby the error being measured by the shortest distance, or perpendicular distance between the tested data point and the surface fit curve. The error related to the shortest distance produces smaller deviations between the tested data and the surface fit than the API error. High pressure LNG pump performance data is utilized to investigate the shortest distance error.