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An Experimental Study to Show the Effect of Time of Opening and Closing the Solenoid Valve on Effectiveness of Finned Cross Flow Heat Exchanger
دراسة عملية لبيان تأثير زمن فتح وغلق الصمام اللولبي على فعالية مبادل حراري مزعنف

Author: سعد سامي فرحان
Journal: Tikrit Journal of Engineering Sciences مجلة تكريت للعلوم الهندسية ISSN: 1813162X 23127589 Year: 2012 Volume: 19 Issue: 3 Pages: 26-35
Publisher: Tikrit University جامعة تكريت

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Abstract

In this research an experimental study was carried out to show the effect of time of opening and closing the solenoid valve on the effectiveness of finned cross flow heat exchanger, which has changed the time of opening and closing the solenoid valve (2, 4, 6 sec.) with change the mass flow rate of water each time and the range values between (0.027-0.0816 kg/s) with constant of mass flow rate of air at (0.032 kg/s). The results obtained from experiment works that the decreasing in the time of opening and closing the solenoid valve from (6 sec.) to (2 sec.) leads to increase internal heat transfer coefficient (hi) the highest increase was by (18.37%) at mass flow rate of water(0.027 kg/s) and increase the overall heat transfer coefficient (U) and the highest percentage of increase (7.36%) at mass flow rate of water (0.027 kg/s). The experimental results obtained show that the increasing both the number of units transmitted (NTU) and effectiveness of the finned heat exchanger when decrease the time of opening and closing the solenoid valve from (6 sec.) to (2 sec.) and the highest percentage of the increase occurring is (8.4%) and (1.74%) respectively at mass flowrate of water (0.027 kg/s).


Article
دراسة عملية لبيان تأثير الصمام النبضي على أداء دورة التثليج الانضغاطية

Author: محمد رضا جواد
Journal: Journal of University of Babylon مجلة جامعة بابل ISSN: 19920652 23128135 Year: 2014 Volume: 22 Issue: 3 Pages: 646-655
Publisher: Babylon University جامعة بابل

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Abstract

In this research, an experimental study the effects of solenoid valve on the performance of compression refrigeration cycle, when it was placed before the evaporator at the refrigeration cycle. Different air temperatures and velocities entering to the evaporator in. Three speeds of the air entering the evaporator which are (3.5, 11.5, 19.5) m / s and four temperatures of the air entering the evaporator are (18, 22, 26, 30) Co. Experimental works were carried out on the refrigeration system for two cases, with and without the solenoid valve.The experimental results Showed that using the solenoid valve increase the coefficient of performance by (8.125%), the refrigerating effect by (1.22%) the compressor work and mass flow rate reduced by(2.4%) and (6%) respect the air velocity (3.5m / s),and the temperature input to evaporator is (30Co).

تم في هذا البحث إجراء دراسة عملية لبيان تأثير الصمام النبضي على أداء دورة التثليج الانضغاطية. تم وضع الصمام النبضي في وحدة التثليج قبل المبخر ولمدخلات مختلفة لسرعة الهواء ودرجة حرارته الداخلة للمبخر، حيث تم استخدام ثلاث سرع للهواء الداخل للمبخر وهي (3.5, 11.5, 19.5) m/s وأربع درجات حرارة وهي (18, 22, 26, 30) Co. حيث إن الاختبارات العملية على منظومة التثليج تم إجراءها لحالتين،الأولى بعدم وجود الصمام النبضي والثانية بوجود الصمام النبضي.أظهرت النتائج العملية بان إضافة الصمام النبضي لدورة التثليج يولد زيادة (8.125%) في معامل الأداء ، والتأثير ألتثليجي يزداد بمقدار (1.22%) ، وشغل الضاغط ينخفض بمقدار (2.4%) والتدفق الكتلي ينخفض بمقدار (6%) عند سرعة هواء (3.5m/s) ،ودرجة حرارة هواء داخلة للمبخر (30Co).

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