Search

This paper designs and simulates a circular heatsink (HSK) with a novel geometry. A number of cylindrical pin-fins (PIFs) are placed on the HSK. The flow of alumina/water nanofluid (NF) enters from the middle of the HSK, passes through the PIFs, goes toward the outer curvature, and exits from the HSK. Constant thermal flux is applied at the bottom of the HSK. The variables include the length of PIFs changing from 5 to 20 mm, the distance between PIFs varying from 10 to 15 mm, and the diameter of PIFs changing from 1 to 4 mm. The effect of these variables on the maximum of the HSK, the average temperature (T-AV) of the HSK is examined. Finally, numerical optimization is done on the results using machine learning and artificial intelligence in terms of the minimum HSK temperature. The flow of NF is simulated using a two-phase model and the finite element method (FEM). An increment in the length of the PIFs from 5 to 20 reduces the T-AV by 11.42 K. An increment in the diameter of the PIFs from 1 to 4 reduces the T-AV of the HSK by 5.98 K. [ABSTRACT FROM AUTHOR]

• A novel algorithm is presented for repetitive transcranial magnetic stimulation. • Tetrahedral mesh used in mesh discretization facilitates the pre-processing. • Our algorithm possesses higher calculation accuracy and faster convergence rate. • The developed model can achieve superior computational efficiency. • The proposed method is suitable for both simple and complex human head models. This paper presents a series of smoothed finite element methods (SFEM) for repetitive transcranial magnetic stimulation (rTMS) based on the quasi-static electromagnetic equations. The problem domain is first discretized into a set of tetrahedral elements and linear shape functions are used to interpolate the field variables. Then the smoothing domains (SDs) are constructed based on the edges, nodes, and faces of the background mesh. The smoothed gradient of electric potential and smoothed magnetic flux density over each SD are obtained by using the gradient smoothing technique (GST). The generalized smoothed Galerkin weakform is utilized to derive the discretized system equations. Numerical examples, including both spherical and realistic shaped heads, illustrate that the SFEM has the following important characteristics: (1) easier pre-processing; (2) better accuracy; (3) faster convergence; (4) higher computational efficiency. [ABSTRACT FROM AUTHOR]

This paper describes the mathematical modeling of a parabolic trough collector where the heat transfer fluid has temperature dependent physical properties for which we have developed our own mathematical expressions. For a specific location and date, the direct solar radiation and other sun–earth parameters are computed on a Julian day basis. Also, we have used certain known and recent correlations for the heat transfer coefficients appearing in this model. The mathematical model is governed by three nonlinear partial differential equations of parabolic type with initial/boundary value conditions. We describe a numerical algorithm in order to obtain the approximate solution of this model. Then, we carry out some numerical simulations which yield valuable information for the performance and efficiency of a solar PTC plant at the specific location. [ABSTRACT FROM AUTHOR]