ISSN: 1813-0410

Keywords : Turbulent flow


Numerical study on forced convection heat transfer and pressure drop for different configurations of corrugated channels

journal of kerbala university, Volume 14, Issue 2, Pages 93-106

A numerical study to investigate the effects of different corrugated channel configurations on the flow and thermal fields are performed with Reynolds number from 6000 to 20000 and heat flux of 6000 W/m2. The simulation adopts FLUENT- based control volume to solve the turbulent flow field and the associated thermal behaviour of the different configurations of corrugation. Seven types, in three groups, of trapezoidal corrugated channels; i.e., one face outward (1FOC), one face inward (1FIC), inward on one face and outward on opposite face (2FIOC). Moreover, two faces inward (2FIC), two faces outward (2FOC), outward and inward are aligned on both surfaces (IAO), and outward and inward are staggered on both surfaces (IOSIO), were examined and compared with smooth one. Simulated results displayed that the 2FIC provides maximum friction factor and heat transfer rate than the others. The performance evaluation criterion (PEC) values decrease with increasing Reynolds number, and the highest was predicted for 1FOC and 2FOC in turbulent flow. PEC comparative evaluation of the influence of flow regime on corrugated channel configurations showed that the (PEC) in laminar regime (600 ≤ Re ≤ 2000) increases and the 2FOC seem to have better values. However, laminar regime offered higher value than the turbulent flow. Computed results are validated as they have an acceptable agreement with the findings of previous works as well as with the existing well-established correlations.اجريت دراسه عدديه لفحص تأثير تفيير هيئة وتصميم القنوات متعرجة السطوح ذات المقطع المستطيل على معدل انتقال الحراره والجريان ضمن مدى لعدد رينولدز من (6000) الى (20000) وبتسليط فيض حراري ثابت وبمقدار (6000 W/m2) .تمت الدراسه باستخدام برنامج فلونت (Fluent-CFD-6.3) والذي يعتمد على تقنية الحجم المحدد لحل المعادلات الحاكمه الخاصه بالجريان الاضطرابي والمتعلقه بانتقال الحراره لمختلف انواع القنوات المتعرجه. اجريت الدراسه لسبعة انواع بثلاث مجاميع لقنوات ذات تعرج على شكل شبه منحرف وهي قناه ذات تعرج لسطح واحد باتجاه الداخل(1FIC ),سطح واحد متعرج والى الخارج (1FOC),سطح باتجاه الداخل والاخر باتجاه الخارج (2FIOC),التعرج لسطحين باتجاه الداخل (2FIC),التعرج لسطحين باتجاه الخارج(2FOC),تعرج لسطحين الى الداخل متعاقب مع تعرج للسطحين الى الخارج(IAO),تعرج الى الخارج يقابل تعرج الى الداخل ويتكرر على طول القناة (IOSIO).وقد تمت مقارنة النتائج مع نتائج لقناة اعتياديه (Smooth Channel).النتائج اظهرت بان أعلى معامل احتكاك وانتقال حراره كان للقناة (1FOC) واقلها للقناة(IAO).لغرض تقييم ثأثير نوع الجريان على أداء القنوات بأعتماد تقييم (PEC) ,فقد أظهرت النتائج ان معامل الاداء يقل بزياده سرعة الماء للجريان الاظطرابي وقد حقق النوع (1FOC) ويليه (2FOC)اعلى قيم بينما كان معامل الاداء يزداد بزيادة سرعة المائع لرقم رينولدز من (600) الى(2000) للجريان الطباقي لحدود معينه من السرعه.تم التحقق من دقة النتائج بمقارنتها مع نتائج العلاقات التجريبيه لهذا الخصوص وكان التطابق مقبول جدا.

A biochemical study of the effect of Neonatal Jaundice on bilirubin concentration level in newborns

Saba Abd Almunam; Rehab Jasem; Master; Rehab Jasem; Mohammed Nofill; Saba Abd Almunam; Areeg Shihab Ahmad; Areeg T.H. Abou-Dareb; Haider Y. Hammod; Adnan H. Ali; Rawa K.Ibrahim; Rewayda Razaq Mohsin; Rewayda Razaq Mohsin; Ali Fawzi Najm AL-Shammari; Alaa M.Alrubae; Rashid J. Abdulah; Ahmed Abdulhadi Ahmed; Haider Galil Al-Qurabi; Ali Abdulhussien Hassan; Eman jabbar K. Alghizzi; Rajaa Jabbar Kadhum; Nadia A. Al-Assady; Sahera G.Sayyah; Ayad I. Haddad; Ahmad A.Hasan; Bushra A.Hasan; EkramA.A; Mohammed K.J; Kawakib J.M; Mohammed J. S. Al-Haidarey; Dafer A. Al-Kufi; Meison A. Al-Selamy; Ibrahim M. Jassim; HASSANEEN JABBAR ABD; Taghreed M. D. Musa; Salam A. H. AL- Ameri; Reyadh M. Ahmed; Ali Aziz Abbas; Shaymaa A. M. Alhashimi; Mustafa T. Al-Kifae; Rassul M. Almaini; Firas Mohamed Abdul Ghani; Ali Farouk; Ahmed Sabeeh Abid Ali Al- Zubaidi; Eman Talib Kareem; ABDULJALEEL HUSSAIN ABD; SALAH NOORI ABBOOD; Hameed Aswad Mohammed; Mohammed Ali Radhy; Nawras Mohammed Shaheed Al-Dahan; Fadhil Ismail Shrrad Al-Taie; Ahmed Ali Abdulsahib Alkarimi; Muhanad Hayder; Sharifi; Hussein Ali Mohammed Al; Saher Ahmed Mohammed Al-Bassam; Maany Abd Al-Moneem Said; Hussein Hadi Abbas; Sareaa Maseer Gatya Al-Mayahie; Muhsen Cadem motleb; JawadKadhim Ali; Hassan Fadhil Al-Husseiny; Buthainah A. Ahmed

journal of kerbala university, Volume 6, Issue 2, Pages 83-89

تم تصميم هذه الدراسة للتحقق في تأثير مرض اليرقان الولادي على مستوى تركيز البيليروبن الكلي والغير مقترن في مصل الأطفال ألحديثي الولادة المصابين باليرقان الولادي (أبو صفار). ولتحقيق هذا الهدف تمت الدراسة على 60 طفل مريض, وقد دلت النتائج على زيادة معنوية ملحوظة (0.005 (p Keywords

Prediction Downpull Force on Tunnel Gate with Different Gate Lip Geometry

Shaymaa A. M. Alhashimi; Mustafa T. Al-Kifae; Rassul M. Almaini

journal of kerbala university, Volume 6, Issue 2, Pages 273-288

Vertical lift tunnel gates are subjected to hydrostatic and hydrodynamic forces produced as a result of operating condition over a wide range of partial openings, discharge and heads. Among these forces is the unbalanced vertical hydrodynamic force resulting from the difference between the downward force on the top of gate within the gate shaft and the upward force on the gate bottom, the net resultant of these two forces is termed as a downpull force. The estimation of downpull force requires the determination of the top and bottom pressure coefficient (KT and KB) which affected by the geometry of gate bottom and the rate of flow passing over the top surface of gate. A two-dimensional CFD model is applied to predict a downpull coefficient (KT and KB) which is named as FLUENT program. The finite volume method is employed on a Reynolds averaged Navier-Stokes equations. The turbulence effects are simulated using the standard (k-ε) model. The simulation model is used for relevant experimental data obtained from hydraulic model tests conducted in laboratory for nine gate lip shape with nine gate openings for each gate lip geometry. The procedure is applied to estimate the pressure coefficients (KT and KB) for different gate bottom geometry. The results illustrate that the inclined gate lip shape with angle of (θ = 35o) given a minimum positive values of downpull force. Also, the downpull coefficient depends mainly on the magnitudes and the distribution of (KB) for a given value of (b2/b1). A general statistical model is built to predict the bottom pressure coefficient for any gate lip geometry.