Numerical and experimental investigation on the effect of restriction shape on characteristics of airflow in a square duct

مقدم أطروحة جامعية

Shattat, Hana Abd al-Hadi H.

الجامعة

الجامعة التكنولوجية

الكلية

قسم هندسة المكائن و المعدات

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2006

الملخص الإنجليزي

Experimental, computational and ready package Fluent (6.1) studies of three-dimensional, fully-developed turbulent air flow in a square cross section duct using restrictions with different shapes and positions for Reynolds numbers ranges of (5.6xl04-+8.2xl04) are presented in this study.

Computational field involves the solution of elliptic partial differential equations for conservation of mass and momentum and their dissipation rate in finite volume form.

These equations are solved together with algebraic expressions for the turbulent viscosity using the (k-s) turbulence model as well as wall function concept near the wall which was used to take the turbulent effects into consideration, for three selected restrictions with different blockage area ratio of (0.11, 0.33 & 0.56) A three-dimensional elliptic finite-domain code was built using Mat-lab language to present general form to simulate the turbulent air flow in the square duct.

Static pressure contours, flow pattern, vorticity contours & velocity distribution are presented.

Fluent (6.1) package is also used to study the same three selected restriction which are used in computational study.

Static pressure contours, vorticity contours and velocity contours at different sections after restrictions are presented in this study.

The experimental ducts test rigs were constructed from Perspex and a five-hole pressure probe was used to measure the air flow velocity vector in space (magnitude and direction).

General computer software was built for calibration of the probe for a wide range of velocities based on experimental data.

Thirteen restrictions with different shapes, positions and blockage areas (0.11, 0.22, 0.33, 0.44 and 0.56) were used in this study.

The results show that the total pressure drop depends on the shape and position of the restriction, and the pressure drop coefficient due to the restriction shape and position (kB) depends on two parameters; blockage area ratio (Ab) and the ratio between wetted perimeter to the free remainder perimeter (pe / Pe) and does not depend on the Reynolds number in study range (for the same blockage area ratio Ab if the pie increases 40 %, the coefficient kR increases 7 %, and for the same Pe / Pc, if the blockage area ratio increases 50 % , the coefficient kR increases 10 %) .

But the pressure drop coefficient due to the friction (Cf) is a function of Reynolds number.

Total pressure coefficient CPI, and axial velocity (U) are also represented in contour form in this study.

التخصصات الرئيسية

الهندسة الميكانيكية

الموضوعات

• النماذج الرياضية
• الأجنحة الحاملة

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305963