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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The torque measured on any instrument will fluctuate with time. A flow nozzle meeting the requirements of this standard is considered a primary instrument and need not be calibrated if maintained in a condition conforming to this standard. The smallest division on the scale of such an instrument should represent not more than 0.
amca 210 07 airflow nozzle
Observations and Conduct of Test ashras. A Pitot traverse duct shall be at least 10 diameters long with the traverse plane located between 8. When making fan law conversions, fan speed has a first power effect on airflow rate. The contribution to the combined uncertainty in ahrae airflow measurement shall not exceed that corresponding to 1.
When a Common part is used: If the settling means are too restrictive, excessive backflow will result. The standard deviation of random errors can be determined by statistical analysis of repeated measurements.
There is also some evidence that performance drops off with a significant decrease in Reynolds number .
AMCA Airflow Nozzle manufacturers – ec
The fan laws should not be employed if it is suspected that the airflow regimes are significantly different because of a difference in Reynolds number. A piezometer ring is specified for pressure measurement at upstream and downstream nozzle taps and for outlet duct or chamber measurement, unless a Pitot traverse is specified.
The geometry of the common segment is adapted from ISO Diameter asyrae has been omitted in Section 7. An airflow straightener shall be used in any duct that provides a measurement plane.
The fan may be tested without outlet duct in which asbrae it shall be mounted on the end of the chamber. When a cell straightener is used: Using test values for Q, Pt, and H with Equations 7. Various dimensionless quantities ashrar in the text.
Groups approve laboratory methods for testing fans.
Auxiliary fans may be used to control the point of test fan operation. Q 5-07 fan power output Ho is proportional to the shaded area which leads to: Reproduction or translation of any part of this work beyond that permitted by Sections and of the United States Copyright Act without the permission of the copyright owner is unlawful. Static pressure taps shall be in accordance with Figure 2A. A duct with a plane for pressure measurement shall be straight and may have either a uniform circular or rectangular cross-section.
Air velocities must be proportional to peripheral velocities. The volumetric airflow rate at fan air density. Plans shall be made to vary the opening of the throttling device in such a way that the test determinations will be well-spaced. East Dane Designer Men’s Fashion. The most elaborate analysis would consider all of the elemental sources of error including those due to calibration, data acquisition, data reduction, calculation assumptions, environmental effects, and operational steadiness.
Since the velocity determination depends on Reynolds Number, an approximation must be employed.
K ; the I-P unit is the foot pound-force per pound-mass degree Rankine ft? Dotted lines on fan inlet indicate an inlet bell and one equivalent duct diameter which may be used for inlet duct simulation.
Air temperature measured by a temperature sensing device without modification to compensate sshrae the effect of humidity.
Groups approve laboratory methods for testing fans.
Transition Piece Notes 1. The velocity pressure corresponding to the average velocity at the fan outlet. Using ideal gas law: When the mean of these readings is greater than Pa 4 in. By making dimension J at least 0. A flow nozzle may be any convenient size except when a duct is connected to the inlet of a flow nozzle, in which case the ratio of flow nozzle throat diameter to the diameter of the inlet duct shall not exceed 0.
An ashras of x and z will reveal that x is the ratio of the totalpressure rise to the absolute total pressure at the inlet, and that z is the ratio of the total-temperature rise to the absolute total temperature at the inlet. Transition Piece Cell Straightener min. However, three or four screens with decreasing percent of open area in the direction of airflow are suggested. If all results were obtained at the same air density, or if results were converted to a nominal air density, that air density shall be listed; otherwise, a plot with air density as ordinate shall be drawn.
Connecting Tubing to Pressure Indicator 6 mm 0. Pressure forces must be proportional aashrae inertia forces. The fan power output Ho would be proportional to ashfae product of fan airflow rate Q and fan total pressure 510-7 if air were incompressible.
When a reaction dynamometer is used to measure torque, the fan power input H shall axhrae calculated from the beam load Fusing the moment arm awhrae and the fan rotational speed N using: The airflow rate Q3 at the Pitot traverse plane shall be obtained from the velocity V3 and the area A3 using: Variable supply system may be an auxiliary fan or a throttling device.