Reynolds number

Змішування в пасивних мікроміксерах залежить від їх геометрії. Отже, багато пасивних мікроміксерів ефективні тільки при великих числах Рейнольдса і вимагають складної структури каналів. Наведено можливості вдосконалення структури Т- мікроміксера для змішування двох рідин з введенням бар’єрів у мікроканалі. У дослідженні ми змінюємо 3 параметри: висоту бар’єра, зсув бар’єра від центру каналу та форму бар’єра. Модель демонструє високу ефективність змішування навіть при малих числах Рейнольдса Re = 0,1.

The sizes of the vortex region before the axisymmetric sudden contraction of the circular pipe at the Newtonian flow have been investigated. Area ratios 0.250 and 0.500 were considered. The sizes of the vortex region have the extreme dependence with a maximum at the transition of the laminar flow into a turbulent flow one. When the Reynolds number at the laminar flow increase, these sizes also increase, and they decrease at the turbulent flow. In both cases, the sizes of the vortex region are proportional to the Reynolds number.

Aim. Development of a method for experimental study of the coefficient of friction for pneumotransport systems of gaseous media using the method of similarity and dimensionality theory, which allows expanding the number of factors and they intervals by grouping them into dimensionless similarity criteria. Method. The planned experiment was chosen for experimental studies of the coefficient of air friction. The main factors were pressure, diameter of the pipeline, air flow.

he current state and trends of air displacement ventilation systems for public and industrial buildings are analyzed. It identified the significant advantages of displacement ventilation.. Disadvantages of the existing diffusers for displacement ventilation. Results of experimental and analytical researches of two-chamber air distribution device unit designs for use in air displacement ventilation in public and industrial buildings are presented in this article. The dependence to determine the dimensions of the structural elements of the air distribution.

Methods for measuring the roughness of the internal surface of a measuring pipeline for projected rectilinear sections of a measuring pipeline and for rectilinear sections that are in operation have been determined. The new equations for calculating the hydraulic resistance coefficient of friction of natural gas on the internal surface of the measuring pipeline, the average value of natural gas pressure along the section of a measuring pipeline and the equivalent roughness were obtained.