Matts-Ohnfeldt Equation

Another modification to the Deutsch-Anderson equation that accounts for non-ideal
effects was devised by Sigvard Matts and Per-Olaf Ohnfeldt of Sweden (Svenska
Flaktfabriken) in 1964. The Matts-Ohnfeldt equation is

The term, wk, the average migration velocity in equation is determined from

information obtained from similar installations. The terms wk and weare similar in that both are average migration velocities. 

The constant, k, in the equation is usually between 0.4 and 0.6, depending on the standard

deviation of the particle size distribution and other dust properties affecting collection

efficiency. However, most people who have used this equation report that a value of k

equal to 0.5 gives satisfactory results (Gallaer 1983 and U.S. EPA 1985). In an Electric

Power Research Institute (EPRI) study, a table was constructed to show the relationship

of predicting collection efficiency using the Deutsch-Anderson and Matts-

Ohnfeldt equations. This information is given in Table

When k = 1.0, the Matts-Ohnfeldt equation is the same as the Deutsch-Anderson

equation. To predict the collection efficiency of an existing ESP when the collection

area or gas flow rate is varied, using lower values for k gives more conservative

results. From Table you can see that the efficiency estimates calculated using the

Matts-Ohnfeldt equation are more conservative than those estimated using the

Deutsch-Anderson equation, and may more likely predict how efficiently the ESP will

actually operate.