تحميل كتاب دراسة نظرية و مختبرية لمضخات الطرد المركزي PDF - اسامة محمد المرضي سليمان

تحميل كتاب دراسة نظرية و مختبرية لمضخات الطرد المركزي pdf تأليف: أسامة محمد المرضي سليمان Osama Mohammed Elmardi Suleiman أستاذ مساعد ، قسم الميكانيكا ، كلية الهندسة والتقنية ، جامعة وادي النيل بسم الله الرحمن الرحيم دراسة نظرية ومختبرية لمضخات الطرد المركزي Theoretical and Experimental Study on Centrifugal Pumps جهاز اختبار مضخات الطرد المركزي ذو المرحلتين بكلية الهندسة ، عطبرة ، السودان Two Stages Centrifugal Pumps Apparatus in Faculty of Engineering, Atbara, Sudan vi Abstract Pump performance is determined from four quantities which are total energy added to the fluid by the pump , flow discharge , power input to the pump shaft and pump shaft speed. Total energy is calculated from the flow and pressure measurements and the other three quantities are measured directly. From the test figures, the gross efficiency can be computed. Additionally, measurements of the net positive suction head, NPSH, may be called for, so that cavitation performance of the pump may be estimated. Every pump regardless of size classification should have at least some kind of performance test before final acceptance by the purchaser. If not, the customer or user does not have any way of knowing that his or her requirements have been fulfilled. Performance tests of pumps and the test methods will depend on the ultimate purpose of the tests. Tests normally fall into one of the two purposes or objectives: Improvement in design, or actual operation, thus enabling any effect on performance by a change or modification in design to be evaluated. To determine if contractual commitments have been met, thus making possible the comparison of specified, predicted, and actual performance. However, the main objective of this research is to run performance test on a centrifugal pump and to study its characteristics. The test apparatus is of a small scale designed as a simple self-contained to permit this study. It is a two-stage unit consists of two identical pumps that may be operated either in parallel or in series, thus permitting a study of a multi-stage pump. It is a specially built scale model pumps made by Plint and partners limited company which specializes in manufacturing engineering education equipment. The experimental results obtained were absolutely satisfactory and almost identical to those provided by the manufacturer. The efficiency of the pump was found to be a low value compared with accepted values for industrial units which reach a value of about 75%. The reason for this low efficiency about 45% is the small size of the vii machine which results in a disport portioned losses (i.e. bearing, gland and skin friction). .