Numerical and experimental investigations of the vortex generators effect in duct heaters

مقدم أطروحة جامعية

Awwad, Afraah Turki

مشرف أطروحة جامعية

al-Khishali, Qutaybah J. M.

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم الهندسة الميكانيكية

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2013

الملخص الإنجليزي

Numerical and experimental investigations were carried out on the effect of two types of vortex generators {circle cross sectional vortex generators and square cross sectional vortex generators }on the flow field and heat transfer from a duct heater.

The flow Reynolds number ranging from 32000< Re <83000 with a constant heat flux of 43.09426 KW/m 2 In the numerical investigation, Fluent package (6.3) was used to solve: steady , (3-D) , continuity , momentum and energy equations with standard (k-e) model was used to remedy the turbulent effects.

Circle cross sectional vortex generators { either small or big circle cross sectional vortex generators } and square cross sectional vortex generators shapes were also used in the numerical study.

Theoretically program {Fluent program} shows that the presence of vortex generators (VGs) would save 27% of heaters power.

The effects of the two shapes of VGs were looked at small circle cross section vortex generators and square cross section vortex generators with same areas.

Also the effects of the two areas of VGs were looked at small circle cross section vortex generators and big circle cross section vortex generators of similar shapes {where R B c c sv G = 1 .

5 }.

R SCCSVG The experimental results showed that there were an enhancement in heat transfer with the presence of VGs and heat transfer depends on VGs shape.

The circle cross section vortex generators was the best shape for enhancing heat transfer.

Also, the [Xd=2cm] distance of VGs rows before or before and in-between heaters rows was the best location for enhancing heat transfer.

The experimental results{temperature values, Nusselt number calculations, and effectiveness calculations}of the flow over heaters with VGs were compared with the flow over heaters without VGs, heat transfer around heaters was enhanced by(2.76-4.11)% using big circle cross section vortex generators and it was enhanced by(2.186 -3.75)% using small circle cross section vortex generators while it was enhanced by(1.3 - 1.94)% by using square cross section vortex generators, all of these values were for 3rows of VGs at Xd=2cm.

The increase of : area of VGs , number of rows for VGs and the distance between each two rows of VGs and the heaters are the most effective parameters in improving the performance of heat transfer.

التخصصات الرئيسية

الهندسة الميكانيكية

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-413121