Pengaruh Variasi Radius Sudu Turbin Angin Darrieus Tipe Sudu-J

Utilization of alternative energy, therefore this wind turbine is used as an alternative energy power plant. So this experimental study is used to determine how much influence on the performance of the Darrieus type J-blade vertical shaft wind turbine by varying the blade radius. The method used is a true experimental research method. The independent variables in this study are variations in wind speed of 3, 4, 5, 6, and 7 m / s. The dependent variable in this research is shaft power and efficiency. Then the controlled variables in this study were the number of blades 3 and the front radius of the blade: 5, 10, and 15 mm. The test results and data processing shows that the blade radius of the Darrieus J-blade type of wind turbine affects the performance of the Darrieus J-blade type wind turbine. In testing the highest value was achieved at a blade radius of 15 mm with a wind speed of 7 m / s, namely the shaft power value of 0.323 Watt and the efficiency value of 4.673%.

Drag reduction in a class 8 truck - scaled down model

Trucks are heavy load vehicles used mainly for commercial transport operations. There are several classes of heavy duty commercial vehicles classified based on the weight loaded. More than 50% of the engine output power in such trucks is utilized to overcome the drag. Drag force in automobiles is the resistance offered by air on vehicles at higher speeds. Class 8 trucks suffer higher drag when compared to other classes. In the present work, a numerical model is developed using a commercial code ANSYS FLUENT to predict the drag coefficient value. The effects of gap width and cab front radius with a constant fairing is analysed using the numerical model developed. A Class 8 model truck with minimal drag coefficient having constant fairing and optimized gap width between the trailer and cab is proposed.

A New Method of Fall-Off Test in Water Injection Well in Tahe Oilfield

In pressure drop well test of the clasolite water injection well of Tahe oilfield, through nonlinear automatic fitting method in the multi-complex reservoir mode for water injection wells, we got layer permeability, skin factor, well bore storage coefficient and flood front radius, and then we calculated the residual oil saturation distribution. Through the examples of the four wells of Tahe oilfield analyzed by our software, we found that the method is one of the most powerful analysis tools.

A Two Dimensional Photoionization Front Model for YSO Envelopes in the Orion Nebula

A simplified axi-symmetric 2.5D radiative transfer model of a YSO envelope (HST-1, 177–341, O’Dell & Wen 1994) in the Orion Nebula (NGC1976) is computed assuming only a spherical distribution of gas with a powerlaw density function. The model fits recent Hubble Space Telescope data (Bally et al. 1996) very well on 1015 cm scales, suggesting that the morphology of the ‘proplyd’ objects is due to photoionization on this scale rather than a direct wind-wind interaction (Henney et al. 1996). The fact that a simple spherical distribution of gas fits the ionization observations so well also implies that somewhere between the scale of the YSO accretion disk and the observed ionization front radius the gas distribution has changed.