Evaluation of the hydraulic aspects for step labyrinth spillway

مقدم أطروحة جامعية

Ujaymi, Taha Yasin

مشرف أطروحة جامعية

Matuq, Jafar Sadiq

الجامعة

الجامعة التكنولوجية

الكلية

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القسم الأكاديمي

قسم هندسة البناء و الإنشاءات

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2013

الملخص الإنجليزي

Stepped spillway draw a lot of attention and their characteristics investigated further.

Stepped spillways in traditional shape have been studied extensively .The modern orientation in stepped spillway research was directed to study the internal two-phase flow nature and modifications on traditional shape for enhancement its performance.

This study was adopted a new concept to enhance performance of stepped spillway towards more dissipation of kinetic energy along chute face through increases interlocking surface areas between the mainstream and trapping cavity recirculation vortices on the chute steps and each step edge that beneath it, and increasing the interaction of the flow interference over stepped spillway.

The aim of this concept is by employment the specification of a labyrinth weir by configured as a stepped spillway, to produce new steps named as Labyrinth stepped spillway.

Experiments were restricted in skimming flow regimes, it have been carried out on twelve physical model are categorized into three groups relative to chute angles (35°, 45°, and 55°).

Each group includes three labyrinth stepped spillway models of three different magnification length ratios LT/W=1.1, 1.2, and 1.3, additionally; a traditional or conventional shape models were used for comparison.

All physical models assembled with step height 4 cm, eight steps constructed for a total height of 32 cm.

The results generally show that the energy dissipation with labyrinth shape stepped spillway was more than resulted with the traditional shape, As the magnification ratio increase above (1) (traditional), the energy dissipation observed to increase that may be attributed to the increasing the interlocking surface areas between the mainstream and trapping cavity recirculation vortices on the chute steps and each step edge that beneath it.

The increase in the magnification length ratio has no significant effect on the flow regimes over stepped spillway.

Also it has no effect on the upper limit of nappe flow and lower limit of skimming flow.

The labyrinth shape having an ability to reduce the effect of a negative pressure values measured at step rises with 35° slope of chute for each magnification length ratio undertaken.

But with chute slopes of 45° and 55°, it has the inversely influence on pressure values (i.e.

increasing the negative value) for LT/W 1.2, especially at mid and near toe of chute.

Whereas, the pressure measured at tread of steps, the labyrinth shape models, for all magnification ratios adopted in present study, tend to decreases, for all flow condition and all chute slopes tested especially at mid and near toe of chute.

التخصصات الرئيسية

العلوم الهندسية والتكنولوجية (متداخلة التخصصات)

الموضوعات

• الهندسة الهيدروليكية
• ميكانيكا الموائع
• المياه
• التوزيع(نظرية اقتصادية)

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-418488