Heat transfer approximate modeling, parameter estimation and thermography of thermal pulsing in electrofusion joints of gas pipelines.

• Thermal pulsing of faultless Electrofusion polyethylene joints is asymmetrically approximated. • The model is experimentally validated by thermography. • PDE constrained parameter estimation & novel geometric coefficients are used to enhance the model. • Thermal efficiency is calculated by using the estimated values of geometric coefficients. Today significantly long distribution pipelines are employed to ensure the availability of natural gas as a clean energy even in the most rural areas. High Density Polyethylene (HDPE) Electrofusion joint has been emerging as the primary means of connection in such HDPE pipelines. Heat transfer has a leading role in the integrity of these joints and clearly a thorough but quick thermal understanding of these joints can be a critical step for effective maintenance and reduction of the associated uncertainties. Therefore, in this study two separate (a primary and a modified) approximate transient heat transfer models are developed to simulate the thermal pulsing of those joints. This pulsing is initiated by converting the electrical into thermal energy within the joint. The modified model is prepared by introducing novel geometric coefficients into the heat source terms by borrowing the idea of skin factors and sphericity coefficients from the petroleum and food engineering domains respectively. Moreover, experimental thermography and TGA are used for validation and design purposes. The results are used to calculate the thermal efficiency of the joint and it was found to be 87.04%. [ABSTRACT FROM AUTHOR]