Experimental study and mathematical analysis of the hydrodynamics in an impinging jet bubble column

مقدم أطروحة جامعية

Ibrahim, Rahiq Ismail

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم الهندسة الكيمياوية

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2006

الملخص الإنجليزي

The present work has been devoted to study and analyze the hydrodynamics (gas hold-up, liquid phase axial dispersion coefficient) and longitudinal concentration of droplet phase in an impinging-jet bubble column (0.1 m inside diameter and 2.25 m height) operating upward co-current gas-liquid-liquid system consisting of air as gas phase, kerosene as dispersed phase, and water as continuous phase.

This column utilized two venture injectors, which were used to [create turbulent gas-liquid jets in the ambient fluid by placing them at : an intersecting angle of 125° and a 60 mm distance between the centers of the nozzles.

A series of experiments were carried out.

The experiments were planned using factorial method for two operating variables : gas superficial velocity, and liquid superficial velocity for single stage bubble column and three stages bubble column.

The minimum and maximum values of the operating conditions used in the experimental work are as follow : - Gas superficial velocity = 0.01-0.018 m / s.

- Liquid superficial velocity = 0.02-0.035 m / s.

The average gas hold-up (ij) for the entire column was measured by two methods bed expansion method, and pressure difference method: the two methods showed a little difference < 5 %, also the local gas hold-up was measured and computed from the pressure difference in each segment used in the column.

The results shows an enhanced values of gas hold-up in the range of gas and liquid superficial velocities used in comparison with conventional bubble columns used in previous works.

The study proved an increasing relationship between the average gas hold-up and both the liquid and gas superficial velocities.

The liquid phase axial dispersion coefficient (DL) for each experimental run was estimated from the pulse response experiment using NaCl solution as a tracer and conductivity electrode as a measuring element.

The results shows an increasing relationship between (DL) and both (uG and uL).

The mean droplet diameter of the dispersed phase was measured using the photographic method, the results shows an increasing relation between dp and liquid phase superficial velocity, while a decreasing relationship was recognized between dp and gas phase superficial velocity.

A mathematical model was formulated to calculate the longitudinal concentration of droplets along the column height, the model predictions agreed with experimental values of C, within 14 %.

The study proved an improvement in the performance of bubble column by installation of perforated partition plates, the gas hold-up values increased by 23 % when placing the partitions.

comparing the results of the present work with those of Kato et Wl (1984) who used a conventional bubble column operating with the same conditions used in present work, indicates that an 58.53 % increase in the average gas hold-up was achieved when using the impingement.

التخصصات الرئيسية

الهندسة الميكانيكية

الموضوعات

• النماذج الرياضية
• ديناميكا الموائع

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-306302