Standard and ANSI/ASHRAE Standard 51, except as modified by Units shall be tested in accordance with ANSI/AMCA Standard /ANSI/ASHRAE. Standard — Laboratory Methods of Testing Fans for Aerodynamic Performance Rating (ANSI/AMCA Standard ) (ANSI/ASHRAE Approved). and Air-Conditioning Engineers (ASHRAE) approved ANSI/AMCA Standard ANSI/ASHRAE Standard , Laboratory Methods of Testing Fans for.
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If both pressure signals are transmitted to the same indicator, the differential is considered velocity pressure at the point of the impact opening. Product details Paperback Publisher: Multi-point or continuous-record averaging can be accomplished with instruments or analyzers designed for this purpose. Each style of azhrae has different conditions, and the required tests are defined for each in these sections.
Airflow conditions can never be completely similar, even for two completely similar fans, if the degree of compression varies. These values converge rapidly, and usually only two or three iterations are required.
An inlet chamber Figure 13, 14 or 15 shall have a cross-sectional area at least five times the fan inlet area. Reverse flow verification test. If the fan has more than one impeller, fan rotational speed is the rotational speed of each impeller.
Since the velocity determination depends on Reynolds Number, an approximation must be employed. A chamber may be used for a variety of fans. A small dimension J may make it difficult to meet the criteria given in Annex A.
All four taps shall be connected to a piezometer ring. A pressure tap is sensitive only to the pressure in the immediate vicinity of the opening. The static pressure at a point shall be measured on an indicator such as a manometer with one leg connected to atmosphere and the other leg connected to a static pressure sensor, such as a static pressure tap or the static tap of a Pitot-static tube.
Similarity and Fan Laws Informative E. The uncertainty also increases rapidly as shutoff is approached. The density of the air corresponding to the total pressure and the stagnation total temperature of the air at the fan inlet.
A duct with a plane for pressure measurement shall be straight and may have either a uniform circular or rectangular cross-section. The air pressure that exists by virtue of the degree of compression and the rate of motion of the air.
amca 210 07 airflow nozzle
Once asbrae airflow settling means have demonstrated that all applicable test criteria have been met, the chamber can be used for all future testing within the limits defined by the test criteria. The equation for efficiency may be rearranged to give either: The difference between the two tare values shall be within 0.
Hg, shall be ashre only for barometric pressure measurements. The fan law equation for fan velocity pressure Pv follows from that for fan total pressure: Some validation tests require that the flow and pressure be determined prior to the settling means having proved their effectiveness. See Figures 13 or 14, Note 5, or Figure 15, Note 6, for requirements. Connecting tubing to pressure indicator shall be asnrae mm 0. The ratio of fan power output to fan power input.
Be the first to review this item Amazon Best Sellers Rank: It is suggested that calculations be carried out to at least 5 decimal places.
The unit of viscosity is the Pascal second Pa? The form of the airflow straightener shall be as specified in Figure 6A or 6B. When the fan discharges directly to atmosphere, the static pressure at the fan outlet Ps2 shall be considered equal to atmospheric pressure, which is zero, so that: When the fan discharges directly into an outlet chamber, the static pressure Ps2 at the fan outlet shall be considered equal to the average chamber pressure Ps7so that: The fan may be tested without outlet duct in which case it shall be mounted on the end of the chamber.
The nozzle throat dimension L shall be either 0. In order to obtain a representative reading, either the instrument must be damped or the readings must be averaged in a suitable manner. The fan total efficiency multiplied by the ratio of fan static pressure to fan total pressure. The fan laws should not be employed if this condition is suspected. This value yields the same power output as the polytropic process over the same range of pressures. Nevertheless, a pre-test analysis is recommended, as is a post-test analysis.
The blades will be arranged to be equidistant on the circumference with the angular deviation being no greater than 5? If the air is at rest, the stagnation total temperature will equal the static temperature. The pressure when the datum pressure is absolute zero. Nozzle shall be in accordance with Figure 4A nozzle with throat taps.