Numerical analysis of heat transfer in mass concrete embedded with multi-pipes via a fast double-layer model based on generalized finite difference method

In simulation of the concrete pipe cooling process, numerical algorithms usually encounter difficulties involving the large-scale ratio, adaptive point strategy, and large-scale computation. In response to these difficulties, excluding simulation of the pipe flow, we have simplified the interesting domain to a two-dimensional model and proposed a double-layer model. The model divides the target domain into two overlapping layers. A virtual circle boundary around the pipe is defined to establish a connection between the double-layers. The temperature field of the area near each pipe with high thermal gradient can be solved in one layer, so as to obtain the solution to the other layer. Meanwhile, the generalized finite difference method with interpolation algorithm and a collocation point strategy has been derived. The analytical solutions to multi-pipes with sharp gradient are derived to obtain calculation accuracy. Numerical results demonstrate the accuracy, stability and efficiency of the proposed scheme, whose elapsed time can be about 10% of the traditional one with the same accuracy. Moreover, a mixed inlets and outlets strategy has been studied to achieve a desired cooling effect.