Advanced Affinity Laws

The performance of a fan is defined by the flow, fan pressure, and power draw of the fan. The fan affinity laws (also called the fan laws for short) are a set of inter-related equations that predict the performance of the fan under varying designs and conditions. For example, from a fan applications perspective, some fan laws dictate how the performance of the fan will vary if we change the density, or the rotational speed of the fan. From a fan design perspective, other fan laws can predict the change in performance due to changes in impeller diameter or size. Yet another even predicts the change in the noise generated by the fan. In this self-guided course, you will apply a simplified set of affinity laws to predict fan performance changes due to changes in rotational speed and changes in density compared to catalog conditions. In high-pressure systems (over 3000 Pa or 12 in w.g.) the compressibility factor must be calculated. Usually when the rotational speed or density changes, the compressibility factor also changes. In this course changes to the compressibility factor are fully considered, and a method from AMCA publication 210 for calculating the compressibility factor is presented. Includes pdf course notes that are handy for future reference, and make it easier for you to follow along, especially if English is not your first language. Includes fan compressibility spreadsheet calculator. Includes IP - SI spreadsheet calculator for unit conversion. You can leave the course and the system will save your progress for when you come back. Explore or re-visit topics in the sequence you desire. Learning activities and quiz questions keep you engaged in the topics. SI units only.