Two models are defined for predicting the trajectory of a foam jet originating from a fire monitor(hydrant)and the related intensity drop point.An experimental framework is also defined and used accordingly to compare...Two models are defined for predicting the trajectory of a foam jet originating from a fire monitor(hydrant)and the related intensity drop point.An experimental framework is also defined and used accordingly to compare real-time data with the predictions of such models.This mixed theoretical-experimental approach is proven to be effective for the determination of otherwise unknown coefficients which take into account several important factors such as the operation pressure,the elevation angle and the nozzle diameter.It is shown that the mean absolute error is smaller than 20%.展开更多
Theoretical analysis of the electromagnetic field distribution in the focal region of a long metallic parabolic reflector that has its surface covered with a magnetized plasma layer is derived. The incident wave is co...Theoretical analysis of the electromagnetic field distribution in the focal region of a long metallic parabolic reflector that has its surface covered with a magnetized plasma layer is derived. The incident wave is considered to be with a general oblique incidence for both parallel and perpendicular polarizations. The electromagnetic field intensity expressions along the focal region are obtained accurately using Maslov＇s method. The effects of plasma thickness on the reflected and transmitted field distributions are investigated. The effects of other physi- cal parameters such as the angle of incidence and the plasma and cyclotron frequencies on the transmitted field- intensity distribution along the focal region are also studied. The results obtained by Maslov＇s method and Kirchhoff＇s approximation are found to be in a good agreement.展开更多
A dish/stifling solar thermal electricity system consists of two parts： a dish solar concentrator and a Stifling engine. For optimizing the system, in this paper, the mathematical model for concentrator design was es...A dish/stifling solar thermal electricity system consists of two parts： a dish solar concentrator and a Stifling engine. For optimizing the system, in this paper, the mathematical model for concentrator design was established and the effects of those design parameters of concentrator, such as the size and intensity of the focal point, the receiver temperature, on the efficiency of the Stifling engine and output power were numerically simulated. The results of the simulation revealed a close relationship between power and efficiency because of power losses, and there was a maximum for the engine efficiency and power with increasing solar radiation because there was a peak value of system efficiency with increasing receiver temperature. So, in view of our Stifling engine, the 450 rim angle and 6m focal length are optimal design for concentrator and the 800℃receiver temperature is best.展开更多
基金the National Key Research and Development Plan(Grant No.2016YFC0801300).
文摘Two models are defined for predicting the trajectory of a foam jet originating from a fire monitor(hydrant)and the related intensity drop point.An experimental framework is also defined and used accordingly to compare real-time data with the predictions of such models.This mixed theoretical-experimental approach is proven to be effective for the determination of otherwise unknown coefficients which take into account several important factors such as the operation pressure,the elevation angle and the nozzle diameter.It is shown that the mean absolute error is smaller than 20%.
基金the Deanship of Scientific Research at King Saud University for its funding of this work through the Research Group Project No. RG-1436-001
文摘Theoretical analysis of the electromagnetic field distribution in the focal region of a long metallic parabolic reflector that has its surface covered with a magnetized plasma layer is derived. The incident wave is considered to be with a general oblique incidence for both parallel and perpendicular polarizations. The electromagnetic field intensity expressions along the focal region are obtained accurately using Maslov＇s method. The effects of plasma thickness on the reflected and transmitted field distributions are investigated. The effects of other physi- cal parameters such as the angle of incidence and the plasma and cyclotron frequencies on the transmitted field- intensity distribution along the focal region are also studied. The results obtained by Maslov＇s method and Kirchhoff＇s approximation are found to be in a good agreement.
文摘A dish/stifling solar thermal electricity system consists of two parts： a dish solar concentrator and a Stifling engine. For optimizing the system, in this paper, the mathematical model for concentrator design was established and the effects of those design parameters of concentrator, such as the size and intensity of the focal point, the receiver temperature, on the efficiency of the Stifling engine and output power were numerically simulated. The results of the simulation revealed a close relationship between power and efficiency because of power losses, and there was a maximum for the engine efficiency and power with increasing solar radiation because there was a peak value of system efficiency with increasing receiver temperature. So, in view of our Stifling engine, the 450 rim angle and 6m focal length are optimal design for concentrator and the 800℃receiver temperature is best.
