Abstract
The modeling of unsteady friction loss in gas pipeline has been studied to improve their accuracy and efficiency because of its importance such as in gas transmission lines and pneumatic control systems. The computation of unsteady friction loss in liquid pipeline is most efficiently and most easily by using the instantaneous acceleration-based (IAB) model. However, IAB model has been derived only in case of liquid pipeline. This paper presents a new equation of the unsteady laminar friction loss in gas pipeline developed by expanding the concept of IAB model to gas pipeline. In general, the unsteady friction loss in gas pipelines is greater than that in liquid pipelines due to the damping effect of the energy equation. The author therefore showed how to take into account the energy equation in the present IAB model. A characteristic solution for unsteady pipe flow is described in which the present IAB model is used to predict unsteady friction loss. Comparisons of numerical test results with measured data from the laboratory experiments and analytical solution by using the high speed and accurate computing method showed excellent agreement. The empirical constants in which the present model includes could be determined by using the approximate curves described in this paper. It was also demonstrated that the developed method requires less computation time and computation memory compared with the high speed and accurate computing method.
