A nanofluid model is simulated by molecular dynamics (MD) approach. The simulated nanofluid has been a dispersion of single walled carbon nanotubes (CNT) in liquid water. Intermolecular force in liquid water has been determined using TIP4P model, and, interatomic force due to carbon nanotube has been calculated by the simplified form of Brenner's potential. However, interaction between molecules of water and atoms of carbon nanotube is modeled by Lennard-Jones potential. The Green–Kubo method is employed to predict the effective thermal conductivity of the nanofluid, and, effect of temperature is sought. The obtained results are checked against experimental data, and, good agreement between them is observed.

Abstract. In this study, shapes of water droplets with di erent sizes on various inclined smooth surfaces are simulated numerically, and advancing and receding contact angles are determined using the molecular dynamics approach. Experimental measurements are also carried out to validate the numerical predictions of droplets' shape on inclined surfaces. Based on the veri ed code, shapes of water droplets with di erent sizes around smooth circular cylinders with various diameters are simulated. Furthermore, advancing and receding contact angles along with the hysteresis values of the sessile and pendant droplets with various sizes around the cylinders are evaluated. Finally, based on the numerical results, two correlations are developed to predict advancing and receding contact angles of droplets on the circular cylinders. According to the results, maximum advancing and minimum receding angles take place on both sides of the cylinder on a horizontal line passing through the cylinder center. As a result, contact angle hysteresis reaches its maximum value in these two positions. In addition, advancing and receding angles have the same values on the top and bottom of the cylinder. Moreover, droplet size and cylinder diameter have minor e ect, while drop position has major e ect on the shape of droplets over the cylinder.

Solar parabolic cooker (SPC) is a simple and an inexpensive equipment which may be used extensively in domestic applications. However, as it is shown in this paper, the 1st law efficiency is very low and the 2nd law efficiency is even lower. For this reason, the performance optimization of cooker is necessary. This optimum performance may be achieved at a specific working temperature. In this paper, the optimization was performed on more than 400 different cases and a simple but useful correlation was proposed to determine the optimum working temperature. It is clear that this optimum temperature in turn, determines the cooker length or fluid mass flow rate.

Adomian decomposition method has been applied to some convection boundary layer problems. It is shown that the method is excellent in solving nonlinear partial differential equations. Comparison of the results so obtained and those from conventional methods proves the technique to be powerful and to give nearly exact solutions. Since most physical problems are governed by nonlinear ordinary or partial differential equations, application of this method may be advised to simplify the method of solution.