**Simulations and Computer Applications**

500 Mechanical Engineering

to 200 m at position B and position C. It is considered that the cavitation occurrence is dominant at the leading edge by the contraction flow and that the bubbles which occur at

As for the effect of velocity distribution, it was clarified in this study that the cavitation noise around a butterfly valve becomes larger when the upstream velocity distribution was different from the normal velocity distribution. It was clear that the interference of the flow from the orifice side and the flow from the nozzle side was suppressed by the fins under not only the normal velocity distribution but also under the biased velocity distribution. The cavitation noise of Type-B was smaller than that of the normal valve in each upstream velocity distribution. Moreover, from the visualization results, it was found that the cavitation bubble diameters ranged from about 20 m to about 200 m and that the

numbers of cavitation bubbles in Type-B was less than that of the normal valve.

Baumann, H.D.,(1991), *Control Valve Primer*, Instrument Society of America, pp.100-107. Itoh, Y., Yamada,M., Oba, R. et al., (1988). *A peculiar Behavior of Cavitating Flow around a* 

Kimura,T. and Ogawa,K., (1986), *Cavitation Vibration and Noise around a Butterfly Valve*,

Kimura,T. and Ogawa,K.,(1997), *Measurement of Cvaitation Erosion Using Fragile Material*,

Kugou, N., Matsuda, H. et al.,(1996), *Cavitation Characteristics of Restriction Orifices* 

Ogawa,K. and Uchida,T., (2005), *Noise reduction of a butterfly valve cavitation by fins and* 

Ogawa,K., (2008), *Noise Reduction in Butterfly Valve Cavitation by Semicircular Fins and* 

Rahmeyer,W.J.,Miller, H.L. and Sherikar, S.V.,(1995), *Cavitation Testing Results for a Tortuous* 

Tani, K., Ito,.Y, and Oba, R., (1991), *Spatial Distributions of Cavitaion Induced Pressure-Pulses* 

Tullis, J.P., (1989). *Hydraulics of Pipelines -Pumps, Valves, Cavitation, Transients-*, John Willey &

Conference, Volume 1, ASME FED-Vol.236, pp.457-462.

*Butterfly Valve*, Transactions of the Japan Society of Mechanical Engineers, Series B,

Transactions of the Japan Society of Mechanical Engineers, Series B, Vol.63, No.606,

*(Experiment on Characteristics of Piping Vibration and Noise*, Fluids Engineering

*improvement of shape of a piping arrangement*, ISA 2005 Technical Conference, (2005),

*Visualization of Cavitation Flow*, 54th International Instrumentation Symposium,IIS-

*Path Control Valve*, Cavitation and Multiphase Flow, ASME, FED-Vol.210, (1995),

*around a Butterfly Valve*, Cavitation and Multiphase Flow Forum, ASME, FED-

the leading edge become smaller in size through pressure recovery.

**9. References** 

pp.360-365.

ISA05-P179.

P047.

pp.63-67.

Vol.109,pp.143-147.

Sons, pp.125-126.

Vol.54, No.508, pp.3317-3224.

Vol.25, No.1, ISA Transactions, p.53-61.

**22** 

*Turkey* 

**Computer Simulation of Involute** 

*Istanbul University, Mechanical Engineering Department,* 

Gearing is an essential component of many machines. From aerospace to high-speed automation, from missiles to submarines, few machines can operate without gears. Involute gears are the most popular power transmission devices for parallel axes owing to their simple geometry, easy manufacturing, and constant gear ratio even when the centre distance has been changed. Spur gears are the most popular form and the most efficient type of gearing for the cost when transmitting power and uniform rotary motion from one

In mass production of gears, generating-type cutters are used. According to the type of relative motion between cutter and gear blank, generating cutters are classified as: rack cutters, hob cutters and gear shapers. Generation cutting is based on the fact that two involute gears of the same module and pitch mesh together - the gear blank and the cutter. This method makes to use one cutter for machining gears of the same module with a varying number of teeth. Rack-type cutters (rack or hob) can only generate external gears. Both external and internal gears can be generated by a pinion-type cutter. Figure 1 displays

For cylindrical gears in applications with uniform load-rotation conditions, an optimized and separate design of traction and thrust flank is desirable. This can be achieved by using different pressure angles for traction and thrust flank, which results in asymmetric tooth geometries. The load-carrying capacity of the gear mechanism can be improved without disturbing the material quality by using asymmetric profiles (Muni et

The computer simulation of gear cutting enables us to investigate the influence of design parameters on the generated profile before manufacturing. Undercutting and zero topland can be detected in design phase. Also the physical behaviour of the gear under operating conditions can be simulated and investigated. Therefore possible faults due to the inaccurate design can be detected for preventing time and material lost. An accurate geometrical representation of gear tooth surfaces is the fundamental starting point for developing a reliable computerized gear design which includes tooth contact analysis and stress analysis.

Therefore, a good knowledge of the gear geometry is required.

**1. Introduction**

parallel shaft to another.

generating-type cutters.

al., 2007).

**Tooth Generation** 

Cuneyt Fetvaci
