ملف المستخدم
صورة الملف الشخصي

فينوس مجيد حميد

إرسال رسالة

التخصص: هندسة كيمياوية

الجامعة: جامعة النهرين

النقاط:

14
معامل الإنتاج البحثي

الخبرات العلمية

  • بروفيسور في الهندسة الكيمياوية
  • حاصل على منحة فلبرايت

الأبحاث المنشورة

An implementation study on a heat sink with different fin configurations under natural convective conditions

المجلة: Case Studies in Thermal Engineering

سنة النشر: 2022

تاريخ النشر: 2022-07-18

This study was conducted as a result of the urgent need to enhance heat sink heat dissipation function emitted by electrical appliances. The effect of new proposed tile fin geometries on its thermal performance in a heat sink under natural convection conditions was investigated. Three different aluminum fin configurations were used at four selected voltage values (37.5, 50, 62.5, and 75 V) and their effect on the studied fin’s performance. The studied heat sink consists of six symmetrical fins. The first fin set type was flat (fin 1), the second one with a rectangular edge (fin 2), and the last one with circular perforations with a rectangular fin edge (fin3). The results were validated with a theoretical correlation which showed a good agreement with acceptable percent error deviation. The experimental results showed that the finned heat sink reached the steady-state conditions faster with less temperature compared to the un-finned heat sink. The average effectiveness of the studied fins is 2.9, 3.1, and 3.3 for fins 1, 2, and 3 respectively. The studied fin (3) dissipated heat 6.8% and 12.9% more than fin 2 and 1 respectively. The efficiency of all proposed fins geometries was above 90%.

Investigating the effect of various fin geometries on the thermal performance of a heat sink under natural convection

المجلة: Heat Transfer

سنة النشر: 2020

تاريخ النشر: 2020-06-28

Experimentally investigates heat dissipation by different longitudinal fins fitted to a cylindrical heat sink under natural convection conditions. Five aluminum fin configurations at base temperatures (70°C, 85°C, 100°C, and 115°C) were studied. The first fin was plain (fin1), while second fin had a triangular edge (fin2). The rest fins have the same triangular edge but with six 1cm circular perforations near the edge (fin3). While the perforations in fin4 were in the middle longitudinal fin length. The last fin (fin5) had twelve 0.5 cm circular perforations distributed into two columns. The measurements were validated with theoretical correlation with an acceptable deviation. The results showed that fin2, fin3, fin4, and fin5 dissipate more heat by 2.4%, 8.7%, 11.4%, and 5% than the flat fin with 9.8%, 11.85%, 11.85%, and 10.82% weight reduction, respectively. The heat transfer coefficient enhanced by 7.98%, 16.81%, 12.35%, and 5.44% for fin5, fin4, fin3, and fin2, respectively. Large circular perforation was more effective to dissipate heat especially when located near the heat source as in fin4 which gives the best heat dissipation with more weight reduction. The proposed fins efficiency were greater than 92%.

Investigation study of vertical helical coil heat exchanger

المجلة: AIP Conference Proceedings

سنة النشر: 2020

تاريخ النشر: 2020-03-14

Modern techniques are invented to promote thermal energy and reduce the size of the heat exchanger. First one is the passive technique which does by adding fluid or change surface geometry. The second way is the active technique, it achieves by using an external force on the surface or fluid or appending a magnetic field to the fluid. Vertical helical coil heat exchanger (VHEX) one of the passive techniques, it is more efficient than straight tube heat exchanger. This PAPER FOCUSES on the comparison between the straight pipe and VHEX. The test consisted of two cases, VHEX and straight tube. Counter water flow was selected as the working fluid in the shell and tube heat exchanger sides. Coldwater was at 30 ᵒC entered to the shell, and the hot water at 60 ᵒC entered to the tube. The flow at the shell was kept constant, while the tube flow was changed. Sixteen experimental runs were one at different flow rates. The results showed the effectivity of the VHEX was better than the straight tube. Heat transfer was increased with increasing water flow rates. Nusselt Number at the straight pipe was less than the helically coiled tube.

Implementation of novel triangular fins at a helical coil heat exchanger

المجلة: Chemical Engineering and Processing - Process Intensification

سنة النشر: 2022

تاريخ النشر: 2022-02-14

Various techniques have been utilized to improve the performance of heat exchangers. In this study, multiple passive enhancement techniques have been applied. Triangular fins have been fabricated on the outside surface of the longitudinal helical heat exchanger. The performance of the new heat exchanger has been investigated experimentally and mathematically. In counterflow, hot water flowed inside the helical tube at 60 ᵒC while cold water entered the shell at 30 ᵒC. A triangle copper fin with 1 cm height, 2 cm base length, and 0.3 cm thickness with 4 cm pitch distance was welded at the external surface of the helical Copper coil tube. Along the helically coiled tube, 123 fins have been welded on the outside surface with 25 overall coil turns heat exchangers. The results showed a good enhancement ratio compared to the unfinned helical heat exchanger. The thermal performance factor showed an improvement of more than 10% compared to plain tube coils with an increase in the effectiveness of 11%. The improvement in the Nusselt number was 16.5%. These results confirmed that the fins addition on the helical coil heat exchanger modified and improved the helical heat exchanger and supported the industrial design with better performance

Experimental Investigation on the Effect of Semi‑circular Perforated Baffles with Semi‑circular Fins on Air–Water Double Pipe Heat Exchanger

المجلة: Arabian Journal for Science and Engineering

سنة النشر: 2021

تاريخ النشر: 2021-07-14

The heat transfer performance of the air–water double pipe heat exchanger (HE) was experimentally investigated. Segmental baffles with semi-circular perforations were introduced in the annular side of HE. Each baffle contains semi-circular fins. Air was used as a working fluid in the annular while, water for the inner tube. Seven different air Reynold’s numbers range from 2700 to 4000 were selected. While water side Reynold’s number fixed at 34,159. Three different semi-circular perforation diameters were studied (30, 25, and 20 mm) to investigate their effect on HE thermal performance. The Nu number, overall heat transfer coefficient, friction factor, and thermal performance factor (TPF) were calculated. Also, compassion for the baffled and un-baffled pipe was done. It was observed that the thermal performance of the baffled pipe HE was better than the un-baffled one. The average overall heat transfer coefficient increases by 29.7%, 62%, and 80.6% by using perforated baffles with 30, 25, and 20 mm perforation diameters. The TPF of the heat exchanger with all studied perforated baffles cases is above unity and the best thermal performance obtained by using baffles was with 20 mm perforation diameter.

Effect of new type of enhancement on inside and outside surface of the tube side in single pass heat exchanger

المجلة: Applied Thermal Engineering

سنة النشر: 2017

تاريخ النشر: 2017-11-11

An experimental investigation was made to study the performance of a double pipe heat exchanger, with a triangular copper fins, which is used to extend the outside surface area of the tube. While, an external type of enhancement is used for the inside of the tube by using twisted tapes with various twisted ratio inserts inside the tube. Results for ninety experiments were indicated. These runs were done for plain tube, finned tube and finned tube with twisted tape at three different twisting ratios. Experiments were performed at various Reynolds number for the above profiles both in the inner and outer tube. The results showed that the overall heat transfer coefficient rate for only a finned pipe is (3 times) greater than plane pipe. Furthermore, as the twisted tape ratio used in the inner pipe at (7, 5, 3), the heat transfer rate was increases 4, 6, 8 times the case of plain pipe, respectively. Conversely, the pressure drop and friction factor increase across the inner tube with the decreasing of the twisted tape ratio increasing. The measured and calculated results show the most effective heat exchanger among cases studied in this which is the finned tube with twisted tape at ratio 3.