Evaluation of linear losses in ventilation ducts with a rounded rectangle cross-section

Kazimierz Peszynski,Václav Tesař,Ewa Kuliś,J Musiał,M Matuszewski,Ł Muślewski,T Kałaczyński

doi:10.1051/matecconf/201930201021

Abstract

The paper presents a new ventilation system characterized by the cross-section of the channels in the shape of a rounded rectangle. The basic research problem was the determination of local losses in the system components. To achieve this goal, it is necessary to know the linear losses in the ducts. The principle of determining both types of losses was presented. The friction coefficients of linear pressure losses referred to the unit of the straight length of the duct section ζl[m−1] as well as generalized dimensionless friction coefficient of linear pressure losses λ [-] is presented. The main achievement of the paper is the statement that the lambda coefficient λ can replace the coefficients ζl examined duct cross-sections.

Highlights

In ventilation systems, as in air conditioning, the basic sections are rectangular and circular sections
18th International Conference Diagnostics of Machines and Vehicles not a surprising result, because it was expected at the same average velocity This result obtained by numerical simulation indicates more even section filling at rounded corners
The coefficient before Arec W H means the indicator of the lost surface of the rectangle as a result of rounding its corners. This coefficient was determined from the formula Arr Arec

Summary

Introduction

As in air conditioning, the basic sections are rectangular and circular sections. Both types have their advantages and disadvantages. Rectangular ducts with rounded corners are analysed, this cross-section is to combine the advantages of both of the above-mentioned shapes of ventilation ducts. 18th International Conference Diagnostics of Machines and Vehicles not a surprising result, because it was expected at the same average velocity This result obtained by numerical simulation indicates more even section filling at rounded corners

Basic parameters of the examined channels

Linear losses

Conclusions