ABSTRACT
Various thermal processes and phenomena need to be studied by experimental methodology. Error or uncertainty analysis is proved to be an important measure to quantify the accuracy and reliability of the experimental results. A large number of thermal-related literatures presented the uncertainty analysis for direct measurements in the data reduction. However, the uncertainties of indirect measurement such as heat transfer coefficient, Nusselt number, friction factor, and developed grouping parameters, which are the final results obtained from direct measured variables, have not been clearly emphasized. This chapter focuses on the uncertainty estimation of indirect measured parameters, which are determined by the functions in terms of multiple direct measured variables. The uncertainty of direct measurement is briefly interpreted involving the standard deviation and normal distribution. The uncertainty of indirect measurement is then introduced emphatically with a case study, based on the analysis of the function formulated by the direct measured variables. The rules in uncertainty propagation for dealing with functions involving addition or subtraction, multiplication or division, and exponent will be interpreted in detail. It is expected that this chapter delivers a quick and handy guide for estimating the uncertainty of indirect measurement by scientific and standard procedures.
