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This paper proposes a new three-dimensional risk assessment model which is based on the traditional two-dimensional risk matrix by adding a new degree of freedom representing the number of overlapped or interacted risk layers. The proposed model uses a geographical information system to managing health and safety through different stages like prevention through design, working safely and responding to undesired situations through providing the required information about spatial based risks. The new model helps the assessor to make realistic hypotheses, avoid uncertainty and improve the accuracy of determining the likelihood and consequences. In addition to the new risk assessment model, a new electronic geographic and safety information communication system is recommended in order to make the new risk assessment model more effective and improve the management of occupational health and safety. The electronic system integrates geographical based data and safety related information to produce risk maps in different places inside and around the workplace. Such a system will facilitate access to data anywhere at all times, enhancing dynamic risk assessment. Finally, the new risk assessment model and the electronic information system are expected to contribute in improving the management of health and safety, assessing risks and preventing losses. [ABSTRACT FROM AUTHOR]

In the present study, the off-design performance of an axial transonic flow fan is predicted. The fan is 2.18 m in diameter, highly twisted, and has a number of 38 tapered blades with a long span and law aspect ratio. This fan is installed in the high bypass ratio CF6-50 turbofan engine. The three dimensional (3-D) flow field is solved in the fan and its intake at different flight conditions. A periodic sector of a central angle of (360/38) is generated to represent the required computational domain. Results show that, at the fan blade inlet, the average relative Mach number reaches unity at 54% and 40% of the blade inlet span for takeoff and cruise conditions, respectively. At the blade tip the relative Mach number reaches 1.38 at takeoff and 1.5 at cruise. Furthermore, the fan map is plotted over a range of speed lines varying from 60% to 110% of the design value. In addition, the surge line and the operating line at cruise conditions are also plotted on the fan map. The efficiency curves for each speed are plotted as well for the same relative speeds. Moreover, computations revealed that at the design speed, approximately 10.5% stall margin remained beyond design pressure ratio. [ABSTRACT FROM AUTHOR]

In modern high bypass turbofan engines, the fan is a considerable component to the performance and efficiency of the entire engine. Fan efficiency directly affects specific fuel consumption of the engine. In the paper, the three dimensional (3-D) flow field through the transonic axial flow fan and the intake of the CF6-50 high bypass ratio turbofan engine is investigated at the takeoff hot day conditions. The fan under study has a large diameter, about 2.18 m. The fan has a number of 38 blades. Each blade is tapered, highly twisted, and has a long span. The real dimensions of both the fan and its intake are used in the current simulation. Furthermore, steady, compressible, turbulent, and viscous flow in both the intake and fan is solved. The computational domain is a periodic sector through both the fan and the intake zones. Results obtained from the simulation show shock waves formed in the passage at the trailing edge of the suction side and propagate towards the opposite blade pressure side. [ABSTRACT FROM AUTHOR]