Head Loss Accessories Calculation Through CFD Does It Worth the Effort?

• Main Author: Catalina Valencia Peroni
• Format: Article
• Language: English
• Published: AIDIC Servizi S.r.l. 2019-05-01
• Series: Chemical Engineering Transactions
• Online Access: https://www.cetjournal.it/index.php/cet/article/view/9941

For several years, head loss calculation of simple piping accessories like tees and elbows was performed through empirical coefficients of well-known equations like Hooper 2 K equation (1981) or Darby’s 3 k equation developed later. As more powerful computers are available nowadays it is reasonable to think that more accurate results could be obtained by using physical phenomena equations like Navier-Stokes. However, Navier-Stokes is difficult to solve in an analytical way for geometries more complex than a sphere or an infinite plane. Time demanding numerical calculation of those equations is needed for simple geometries like elbows and tees. Computational fluid dynamics (CFD) solves numerically Navier-Stokes. Software that implements CFD has usually a high step in the learning curve, even more for a pregrad chemical engineering student that is not familiar with 3D Cad modelling. In this work two different commercial software results i.e. Fluent Ansys and Solid Works Flow Simulation are compared with traditional Hooper’s 2K calculation for head loss on elbows and tees through 117 CFD simulations of chemical, biological and mechanical engineering students. CFD results follow the experimental data contained in Hooper paper but are numerically different of those obtained through Hooper equation. Some possible explanation for this is discussed here. Also, CFD software learning curve for the students categories is analyzed concluding that for a fresh chemical engineer CFD is preferable for complex accessories where no experimental data is available although if you can get over the first step on the learning curve you become the owner of a powerful tool.