Numerical Prediction of a Radial Turbine Performance designed for Automotive Engines Turbocharger

في الوقت الحاضر تقنية الشاحن التوربيني يلعب دوراً أساسيا في تحسين أداء محركات السيارات، وتخفيض استهلاك الوقود وانبعاثات العادم، في  محركات الكازولين والديزل. أداء التوربين الشعاعي لجهاز الشاحن التوربيني يتأثر بشدة بديناميكية الجريان في المكرة القطرية.  علاوة على ذلك، تعديل وتحسين مكرة التوربين القطري مهمة صعبة لمهندسين المكائن التوربينية. ولهذا الهدف من هذه الدراسة لزيادة تحليل ديناميكية الجريان الحسابية على اداء طور التوربين القطري.  خصائص التصميم لطور التوربين القطري، استخدمت لمحاكاة الجريان باستخدام مجموعات مستقلة من ANSYS CFX. الدراسة المقارنة لمحاكاة التدفق الثلاثي الأبعاد سوف تعطي نتائج أكثر واقعية لسلوك الجريان داخل طور التوربين ومحاكاة CFD يمكن أن تعطي نتائج أكثر تفصيلاً وتكشف عن سلوك الجريان غير متوقعة مثل انفصال الجريان والدوامات. أظهرت النتائج أن ديناميكية جريان المائع داخل طور التوربين بينت بشكل ملحوظ خصائص الاداء. ومن الواضح أن نسبة الانضغاط ومعدل حجم التدفق والكفاءة تم تنبؤها عددياً. بشكل عام النتائج العددية التي تم الحصول عليها من محاكاة ديناميكية الجريان الحسابية يمكن ان تقدم درجة عالية من الدقة لتخمين اداء التوربين القطري للشاحن التوربيني.These days the turbocharging system is assuming an essential part in enhancing car engines performance and diminishing fuel utilization and the fumes emanations, in spark-ignition and compression ignition engines. The performance of a radial turbine for the turbocharger device is heavily affected by the flow dynamics in a radial impeller. Furthermore, modification and improvement of a radial turbine impeller is a challenging task for turbomachinery engineers. Hence, this study aimed to further computational fluid dynamic analyses of a radial turbine stage performance .The design characteristics of a radial turbine stage,  was used to simulate the flow by using independent packages of ANSYS CFX. The comparative study of a three dimensional flow simulation will give a more reasonable results of the turbine stage flow behavior and computational fluid dynamic simulation can give a more detailed result and reveal unexpected flow behavior like separation and vortexes.The results showed that the fluid flow dynamics within a turbine stage has indicated a noticeable performance characteristics. Obviously, it was observed that the pressure ratio and volume flow rate and efficiency were predicted numerically. Overall  numerical results obtained from computational fluid dynamic simulations could produce a highly reliable for estimation on the performance a radial turbine of turbocharger

Design and Performance Investigation of a Hydraulic Mini Turbine Based on Renewable Energy Production System

في الوقت الحاضر اهتمام كبيرة لانظمة إنتاج الطاقة المتجددة منذ السنوات القليلة الماضية. شهدت مصادر الطاقة المتجددة مثل الطاقة المائية والطاقة الشمسية وطاقة الرياح نمواً سريعاً، لا سيما الطاقة الكهرومائية بسبب تزايد ندرة الوقود الأحفوري والقضايا البيئية. توربين كابلان هو أحد انواع انتاج الطاقة الكهرومائية ومن المصادر الرئيسية للطاقة المتجددة. في هذه الدراسة، يهدف هذا العمل إلى تصميم وفحص أداء عجلة توربين كابلان لتحديد ناتج الطاقة وكفاءتها استنادًا إلى الانواع المختلفة لعجلة التوربينات. الخصائص الرئيسية الأساسية للتصاميم المقترحة لتوربين كابلان الصغير اجريت وذلك لزيادة استخدام الطاقة المتجددة في المناطق الريفية وتقليل الاعتماد على الوقود الأحفوري. تم استخدام ديناميك الموائع الحسابية (CFD) لمحاكاة التصاميم المقترحة للتعرف على مزيد من التحليل وتحسين كلاً من القدرة الخارجة والكفاءة باستخدام ANSYS CFX17.1. وقد تم التنبؤ بأداء توربين كابلان الصغير مثل القدرة الخارجة والكفاءة. علاوة على ذلك، أظهرت النتائج ان عدد الريش يؤثر بشكل كبير على اداء التوربينات وكفاءتها. بشكل عام قدمت تحسينات للتصاميم المقترحة وذلك لفهم مجال الجريان داخل عجلة توربين كابلان.Nowadays great interest of renewable energy production systems since last few years. The renewable energy sources such as a hydro, solar and wind have been rapidly growing, especially the hydropower energy due to the increasing of predicted scarcity of fossil fuels and the environmental issues. Kaplan turbine is a reaction type of hydropower which is one of the primary sources of renewable energy. In this study, the aim of this work is to design and performance investigation of a Kaplan turbine runner for determining the power output and efficiency based on different configurations of turbine wheel. The main characteristics of a micro Kaplan turbine primary proposed design configurations was performed to increase the use of renewable power in rural areas and reduce the dependence on fossil fuels. The computational fluids dynamics (CFD) was used to simulate the proposed design for further analysed and improve both the power output and efficiency using ANSYS CFX17.1.The performance  of a micro Kaplan turbine has been predicted such as power output and efficiency. Furthermore, the effect of blades number showed a significant influence on the turbine’s power output and efficiency. Generally, improvement of proposed design configurations are presented for understanding the flow field in a Kaplan turbine runner

Aerodynamic design and performance investigation of an axial turbocharger turbine for automotive application

In recent years, developments of vehicle downsizing promote the developers to improve the performance of current turbocharging technology. Due to drawbacks transient response of conventional radial turbine used in turbocharging techniques, preliminary design of axial turbine was proposed, in order to achieve highest performance of turbocharger axial turbine. In this study, the optimal design methodology, based NACA profile blade of a single stage axial turbine for turbocharger system. Therefore, simulation analysis of steady state three dimensional flow carried out by highly reliable for calculation, computational fluid dynamic (CFD), using ANSYS CFX, to be evaluated the stage overall aerodynamic performance of the axial turbine stage. Analysis results, gave a more details of flow behaviour such as, flow separation, vortexes and performance characteristics. Moreover, it is found the pressure load for less blades, it's too low on each blade, and a reasonable pressure blade load on a single blade was therefore seen to be too high for more blades, resulting in loss of Boundary layer of the blade, flow of tip leakage and Secondary flow. Hence, noticeably, it was observed that the aerodynamic performance of turbocharger axial turbine model were predicted numerically such as, total-total Polytropic efficiency (84.64) % and shaft output power (187) kW at (80k) rpm

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population