Informatics Publishing Limited

Akram Zeid ¹, Ahmed Farag ²

Affiliations
1 Marine Eng. Technology Dept., College of MT.
2 T, AASTMT, Alexandria, EG

Abstract

This paper presented a study of the natural gas combustion in a swirl gas turbine combustor. The effect of the primary air swirl number, primary air/fuel mass ratio and the secondary/primary air mass ratios on the flow field and combustion characteristics of natural gas in air is investigated. For this purpose, a test rig was constructed including a vertical test combustor provided with an air swirler mounted at its upstream. Primary air, secondary air, and fuel lines are also included. Four different air swirlers having the same blockage ratio of 0.72 are used for the present investigation. The swirlers have the same hub (inner) diameter of 72 mm and the same outer diameter of 100 mm. The swirlers have different vane angles of 15^o, 30^o, 45^o, and 60^o to generate swirl numbers of different strengths of about 0.23, 0.5, 0.85 and 1.5, respectively. A three dimensional model was used to simulate the non reacting and reacting flows by using the computational fluid dynamics package Fluent 6.3. Comparing the measured test data with the numerical computations, a reasonable agreement is found. The results show that, increasing the primary air/fuel ratio and the secondary/primary air mass ratio leads to decreasing the average flame temperature and consequently the flame size. Increasing the secondary/primary air mass ratio leads to a decrease in the axial CO and CO₂ concentrations and an increase in O₂ concentration at the combustor exit.

Keywords

Gas Turbine Combustor, Swirl Number, Secondary Air, Natural Gas Combustion Characteristics

Full Text

     

Ahmed Farag ¹, Hany M.S. Mikhail ², Ahmed S. Khalifa ³, Mohamed T. Mostafa ³, Abdrabou N. Mashhour ²

Affiliations
1 Professor of General Surgery, Cairo University, EG
2 Assistant Professor of General Surgery, Cairo University, EG
3 Assistant Lecturer of General Surgery, General Surgery Department, Cairo University, EG

Abstract

Objective: The aim of the present prospective study was to evaluate the role of preoperative prophylactic biofeedback therapy on the anorectal continence of patients with high anal fistula who will be subjected to fistulectomy operation. Method: This was a randomized control study which included 40 patients who presented to the Out Patient Department (OPD) of Kasr‑al ainy Hospitals, from March 2015 to September 2016. Allpatients (40) have been presented with high complex anal fistulae. They were divided into two equal groups; group (A) has twenty patients who had undergone prophylactic preoperative anorectal biofeedback and group (B) has the other twenty patients who didn`t receive the prophylactic preoperative anorectal biofeedback therapy. For group (A) patients, six sessions of biofeedback were done two weeks. All patients were assessed postoperatively (0, 3 and 6 months) for continence by Cleveland Clinic Score for incontinence. Results: Among these forty patients only four (10%) had developed anal incontinence with variable degrees (two of them gas incontinence and another two developed frank stool incontinence), these four patients belong to the group (B), on the other hand, none of group (A) patients had developed incontinence. Conclusion: In conclusion, we can rely on preoperative prophylactic biofeedback has an important role to minimize incontinence post high anal fistula surgery.

Keywords

Fistula in ano, Fecal Incontinence, Biofeedback.

Full Text