(39a) The Ergun Equation: Right or Wrong?

When it comes to fluid flow through packed beds, the Ergun equation is the most popular model for relating fluid pressure drop to flowing fluid Reynolds number. The popularity of this equation results from it being

• presented in most engineering texts concerned with such flow;
• taught as “the gospel” in most top-tier engineering schools.

Thus, future engineers leave university with the Ergun equation well-represented in their intellectual toolkit.

Unfortunately, the Ergun equation rests upon shallow foundations laid in shifting sands. Basically, the Ergun equation is nothing more than the addition of the Blake-Kozeny and Burke-Plummer equations, both of which contain a plethora of questionable assumptions.

This presentation reports an experimental test of the Ergun equation and discusses the theoretical foundations of the Ergun equation.

This presentation also contains a “new look” at fluid flow through packed beds and demonstrates how to scale packed beds from laboratory-sized equipment to commercial-sized equipment.