Convergent part

Equation (1.54) indicates that A/A becomes minimal at M = 1. The flow Mach number increases as A/A decreases when M < 1, and also increases as A/A increases when M > 1. When M = 1, the relationship A = A is obtained and is independent of Y- It is evident that A is the minimum cross-sectional area of the nozzle flow, the so-called nozzle throat", in which the flow velocity becomes the sonic velocity, furthermore, it is evident that the velocity increases in the subsonic flow of a convergent part and also increases in the supersonic flow of a divergent part. 

A nozzle used for a rocket is composed of a convergent section and a divergent section. The connected part of these two nozzle sections is the minimum cross-sectional area termed the throat The convergent part is used to increase the flow velocity from subsonic to sonic velocity by reducing the pressure and temperature along the flow direction. The flow velocity reaches the sonic level at the throat and continues to increase to supersonic levels in the divergent part. Both the pressure and temperature of the combustion gas flow decrease along the flow direction. This nozzle flow occurs as an isentropic process. 

A feeder usually consists of a vertical part called the bin and a converging part called the hopper. In the storage bin, the bulk solids normal stress increases linearly with depth due to the weight of individual particles while they transmit static shear forces. Stress at the wall quickly reaches a... 

It is shown in specialized texts on fluid dynamics that a convergent-diveigent nozzle is needed to accelerate a gas from subsonic to supersonic conditions, since gas acceleration in the subsonic regime requires the flow area to diminish with speed, while gas acceleration from sonic to supersonic speeds requires the flow area to expand with speed. The subsonic, convergent part of the nozzle is linked to the supersonic, divergent part of the nozzle by a duct of constant flow area, known as the throat, which is kept very short in practice in order to avoid frictional losses. The throat is the only section of the nozzle in which sonic flow can occur, and it is impossible for the throat to support any speed greater than sonic. The above remarks apply to all polytropic... 

Very little energy is lost to friction in the convergent part of any nozzle, and so we may write down the velocity at station 2 by using equation (5.22), setting n = y for frictionless, adiabatic flow ... 

Oc over convergent part of nozzle in critical conditions... 

The various sections of the venturi such as the converging part, throat, and diverging part shall be easily separable for cleaning. Hence, they shall be bolted together by flanged connections. 

Before coming back to Fig. 5 to show and discuss some examples, the doming -no doming criterion has to be explained, qualitatively and quantitatively [1,2]. In Fig. 7 several stresses are plotted versus height for a mass flow silo. The silo consists of the vertical part, the bin, and the converging part, the hopper, with its apex at height h = 0. 

Somewhat contrary results were obtained when a dimpled-surface thrust bearing was tested at low speeds (below 1 m/s) and loads of up to 3.45 MPa [67]. The bearing was of a bending-pad type with three pads rotated in an oil bath with a stationary collar. The measured pressure profiles had bumps in the converging part of each dimple. It was concluded that they could improve load capacity. The study also revealed that depending on Sommerfeld number the friction coefficients of the dimpled bearing were up to 7.3% lower than those associated with a plain surface. Unfortunately, dimple dimensions were not given. 

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