بررسي تجربي ساختار ماتريسي بر كاهش نوسانات فشار جريان خروجي فن گريز از مركز

چكيده انگليسي :

146 Experimental Investigation of Honeycomb Effect Reducing Pressure Fluctuation of the Outflow in Centrifugal Fan Mohsen Rezaie Kupaie Mrezaie iut@yahoo com 18 06 2011 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervior Dr Mohsen Davazdah Emami Mohsen@cc iut irAbstractThe most important factors in assessment of industrial devices are performance and efficiency The present studyaims to investigate these features for centrifugal fans It is intended to use a comprehensive data acquisitionsystem to evaluate the performance and efficiency and fan system This is done by measuring flow rate and staticpressure across different sections of a pipe connected to the fan outlet One of the most important applications offan is in burner systems where an appropriate ratio of oxidant to fuel flow rate obtained by adjusting the fan airflow rate The present study tries to find an inhibiting mechanism to reduce the flow fluctuations at the outlet ofthe fan and the inlet of the burner The present report starts with an introduction to different fans and their features General rules concerningcentrifugal fans are described Next different standard methods for fan testing and their required equipment areexplained in details Mathematical formula and their degree of accuracy are presented The designed test rig andit is manufacturing procedure is explained in details A paramount feature of this test ring is the data acquisitionsystem which is designed and built during present study In the current study most of the measuring system isbuilt by the author and only the standard sensors are used as the materials for constructing the data acquisitionsystem The present study focuses on detecting and diminishing pressure fluctuations in the fan out flow Digital pressuresensor in the range of 0 50 mbar with electrical output of 4 20 mA are used to detect pressure fluctuations Pitot tubes are also used at different sections of the test rig The stagnation pressure is measured at a standarddistance of the inlet to calculate the velocity profile from which the mass flow rate in the outlet pipe can becalculated In order to inhibit the pressure fluctuations honeycomb matrix of 3 mm and 5 mm characteristicdimensions All the manufacturing and testing procedures are done based on ACMA standards The outlet pipediameter is chosen such that the fan diffuser diameter match the pipe to avoid the formation of eddies at the jointsection Note that due to the speed of the acquisition system it is possible to record data for transient cases Allthe measured data can be stored as an EXCEL file Measurements are repeated to ensure that the results are notaffected by external parameters The fan performance curve has also been obtained by measuring flow rate andstatic pressure in the range of fan operational data This is done by increasing the flow rate from near zero up tomaximum opening in the fan inlet damper Results show that using honeycombs especially the smaller size considerably inhibit pressure fluctuations and lead to a uniform velocity profile However the price paid is anincrease in the pressure drop in flow Therefore it is up to the designer to find a compromise between therequired pressure level of the fan outlet and the fluctuation level in the flow field characteristics Key wordsFan Pitot Tube Honeycomb Data Acquisition System

رضائي كوپايي، محسن

بررسي تجربي ساختار ماتريسي بر كاهش نوسانات فشار جريان خروجي فن گريز از مركز

پيتوت , لانه زنبوري , سيستم داده برداري