ASME PTC 11-2008 pdf download
ASME PTC 11-2008 pdf download.Fans.
1-1 OBJECT This Code provides standard procedures for conducting and reporting tests on fans, including those of the centrifugal, axial, and mixed flow types. 1-1.1 Objectives The objectives of this Code are to provide: (a) the rules for testing fans to determine performance under actual operating conditions (b) additional rules for converting measured performance to that which would prevail under specified operating conditions (c) methods for comparing measured or converted performance with specified performance 1-1.2 Principal Quantities The principal quantities that can be determined are (a) fan mass flow rate or, alternatively, fan volume flow rate (b) fan specific energy or, alternatively, fan pressure (c) fan input power Henceforth, these parameters shall be inclusively covered by the term “performance.” 1-1.3 Additional Quantities Additional quantities that can be determined are (a) gas properties at the fan inlet (b) fan speed Henceforth, these parameters shall be inclusively covered by the term “operating conditions.” 1-1.4 Other Quantities Various other quantities can be determined, including (a) fan output power (b) compressibility coefficient (c) fan efficiency (d) inlet flow conditions 1-2 SCOPE The scope of this Code is limited to the testing of fans after they have been installed in the systems for which they were intended. However, the same directions can be followed in a laboratory test. (The laboratory test performance may not be duplicated by a test after installation because of system effects.) The term “fan” implies that the machine is used primarily for moving air or gas rather than compression. The distinction between fans, blowers, exhausters, and compressors in common practice is rather vague; accordingly, machines that bear any of these names may be tested under the provisions of this Code. (It is conceivable that these machines can also be tested under the provisions of PTC 10, Compressors and Exhausters.)
2-2 DEFINITIONS 2-2.1 Temperature absolute temperature, T : the value of temperature when the datum is absolute zero. It is measured in kelvins or degrees Rankine. The absolute temperature in degrees Rankine is the temperature in degrees Fahrenheit plus 459.7, and the absolute temperature in kelvins is the temperature in degrees Celsius plus 273.2. dry-bulb temperature , t d : the temperature measured by a dry thermometer or other dry sensor. static temperature, t s , T s : the temperature measured in such a way that no effect is produced by the velocity of the flowing fluid. It would be shown by a measuring instrument moving at the same velocity as the moving fluid. Absolute static temperature is used as a property in defining the thermodynamic state of the fluid. total temperature, t t , T t : sometimes called stagnation temperature , the temperature that would be measured when a moving fluid is brought to rest and its kinetic potential energies are converted to an enthalpy rise by an isoenergetic compression from the flow condition to the stagnation condition. At any point in a stationary body of fluid, the static and total temperatures are numerically equal. wet-bulb depression, t d − t w : the difference between the dry-bulb and wet-bulb temperatures at the same location. wet-bulb temperature, t w : the temperature measured by a thermometer or other sensor covered by a water-moistened wick and exposed to gas in motion. When properly measured, it is a close approximation to the temperature of adiabatic saturation.
2-2.2 Specific Energy and Pressure absolute pressure, p a : the value of a pressure when the datum is absolute zero. It is always positive. barometric pressure, p b : the absolute pressure exerted by the atmosphere. differential pressure, Δ p : the difference between any two pressures. gage pressure, p : the value of a pressure when the datum is the barometric pressure at the point of measurement. It is the difference between the absolute pressure at a point and the pressure of the ambient atmosphere in which the measuring gage is located. It may be positive or negative. pressure, p : normal force per unit area. Since pressure divided by density may appear in energy balance equations, it is sometimes convenient to consider pressure as a type of energy per unit volume. specific energy, y : energy per unit mass. Specific kinetic energy is kinetic energy per unit mass and is equal to one-half the square of the fluid velocity. Specific potential energy is potential energy per unit mass and is equal to the gravitational acceleration multiplied by the elevation above a specified datum. Fluid pressure divided by density is sometimes called “specific pressure energy” and is considered a type of specific energy; however, this term is more properly called specific flow work. static pressure, p s , p sa : the pressure measured in such a manner that no effect is produced by the velocity of the flowing fluid. Similar to the static temperature, it would be sensed by a measuring instrument moving at the same velocity as the fluid. Static pressure may be expressed as either an absolute or gage pressure.
