Flow axial

An alternative type of downhole mud motor is the mud turbine, (multistage axial flow turbine) which directly drives the bit. The tool consists of an upper section containing the turbine blades and lower section with bearings. As mud is pumped through the upper section the blades are turned. Turbines are designed to rotate at higher speed than the displacement motor. The higher rotation speed requires diamond or composite bits. 

Fig. 9. Types of axial-flow fans where the dashed arrows denote the direction of air flow (a) propeller fans (b) tube-axial fans (c) vane-axial fans (17).

Fig. 10. Performance characteristics for axial flow fans ( ndashrule ), ptopeUet fan (—), tube-axial fan and ( ), siagle-stage and (.), two-stage...

The servo voltage is a function of mass-flow rate. Axial-flow angular-momentum meters are sometimes used in measuring jet engine fuel flow as the fuel energy content correlates much mote closely with mass than volume. 

Stea.m-Ra.ising Converter. There are a variety of tubular steam-raising converters (Fig. 7d) available, which feature radial or axial flow, with the catalyst on either shell or tube side. The near-isothermal operation of this reactor type is the most thermodynamically efficient of the types used, requiring the least catalyst volume. Lower catalyst peak temperatures also result in reduced by-product formation and longer catalyst life. 

Catalyst Particle Size. Catalyst activity increases as catalyst particles decrease in size and the ratio of the catalyst s surface area to its volume increases. Small catalyst particles also have a lower resistance to mass transfer within the catalyst pore stmcture. Catalysts are available in a wide range of sizes. Axial flow converters predorninanfly use those in the 6—10 mm range whereas the radial and horizontal designs take advantage of the increased activity of the 1.5—3.0 mm size. 

Centrifugal, including radial, mixed flow, and axial flow designs... 

Frame-mounted ANSIB73.1 Wet-pit volute Axial flow impeller (propeller) volute type (horizontal or vertical)... 

Axial-Plow Propeller-Type. The axial-flow propeUer-type pumps are used to handle large volumes of pumped Hquid at low head. Flow rates of >12 m /s (>200,000 gal/min) can be accommodated. 

A. S. Berman, A Simplified Modelfor the Axial Flow in a Tong Countercurrent Gas Centrifuge Rept. K-1535, Union Carbide Corp., Nuclear Div., 1963. 

Fig. 11. Two-truck tray dryer. A, air inlet duct B, air-exhaust duct with damper C, axial flow fan D, fan motor, 2—15 kW E, air heaters F, air-distribution plenum G, distribution slots and H, wheeled tmcks and trays. The arrows iadicate air and vapor flow pattern.

FIG. 6-39 Typical stirred tank configurations, showing time-averaged flow patterns for axial flow and radial flow impellers. From Oldshue, Fluid Mixing Technology, McGraw-Hill, New Yo7 k, 1983.)... 

Axial-Flow Transverse-Momentum Mass Flowmeter. 10-19... 

General Principles There are two main types of mass flowmeters (1) the so-called true mass flowmeter, which responds directly to mass flow rate, and (2) the inferential mass flowmeter, which commonly measures volume flow rate aud flmd density separately. A variety of types of true mass flowmeters have been developed, including the following (a) the Maguus-effect mass flowmeter, (b) the axial-flow, transverse-momentum mass flowmeter, (c) the radial-flow, transverse-momentum mass flowmeter, (d) the gyroscopic transverse-momentum mass flowmeter, aud (e) the thermal mass flowmeter. Type b is the basis for several commercial mass flowmeters, one version of which is briefly described here. 

Axial-Flow Transverse-Momentum Mass Flowmeter This type is also referred to as an augiilar-momeutum mass flowmeter. One embodiment of its principle involves the use of axial flow through a driven impeller aud a turbine in series. The impeller imparts augiilar momentum to the fluid, which in turn causes a torque to be imparted... 

Mechanical Impulse The principle of mechanical impulse when applied to fluids is usually combined with one of the other means of imparting motion. As mentioned earher, this is the case in axial-flow compressors and pumps. The turbine or regenerative-type pump is another device which functions partially oy mechanical impulse. 

Figure 10-35 shows the schematic of specific-speed variation for different types of pumps. The figure clearly indicates that, as the specific speed increases, the ratio of the impeller outer diameter Di to inlet or eye diameter Do decreases, tending to become unity for pumps of axial-flow type. 

Axial-Flow (Propeller) Pumps (Fig. 10-44) These pumps are essentiahy very-high-capacity low-head units. Normally they are designed for flows in excess of 450 mVh (2000 gal/min) against heads of 15 m (50 ft) or less. They are used to great advantage in closed-loop circulation systems in which the pump casing becomes merely an elbow in the line. A common installation is for calandria circulation. A charac teristic cui ve of an axial-flow pump is given in Fig. 10-45. 

FIG. 10-44 Axial-flow elbow-type propeller pump. Cowtesy of hawrence Pumps, Inc.)... 

FIG. 10-45 Cbaracteristic curve of an axial-flow pump. To convert gallons per minute to cubic meters per hour, multiply by 0.2271 to convert feet to meters, multiply by 0.3048 and to convert horsepower to kilowatts, multiply by 0.746. 

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