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تحسين الاداء الحراري للمائع النانوي في المبادلات الحرارية Enhancement Of Thermal Performance Of Nanofluids In Heat Exchangers

المستخلص: التقنية الواعدة التي تستخدم لتعزيز عملية الانتقال الحراري هي باستخدام الموائع النانوية كخيار جيد واستبدالها محل السوائل التقليدية الشائعة. والمبادلات الحرارية هي معدات واسعة التطبيق في كثير من التطبيقات الصناعية المختلفة وبالتالي يكون سلوك وخصائص المائع | The most promising technique that is used to enhance the thermal performance for the heat transfer processes is using the nanofluids as a good choice to replace the conventional fluids. The heat exchangers are the wide range application equipment that is used for different industrial applications and therefore, the properties and the behavior of the fluid media are the main control parameters in equipment design of the heat exchangers. In this work an attempt was made to investigate experimentally the thermal performance of nanofluid which consists of deionized water (DI) as a base fluid and Aluminum oxide (Al2O3) as solid nanoparticles. The investigation includes two parts, the first one is studying the effect of addition of solid nanoparticles to the base fluid on the thermo - physical properties such as density, viscosity and thermal conductivity for different values of the volume fraction of nanoparticles. The second part includes the experimental work studying the effect of the nanoparticles (Al2O3) volume fraction (0.05, 0.1 with base fluid ), heat flux (With three values 7.4W,11W,16.8W) and angle (With two values 90?,45?) with four models (four different type from wicks in heat pipe) to enhance the heat transfer in heat pipe with two cases of transient temperature distribution and steady state. One model is different from the other by using different wicks in a heat pipe in all models. The general results referred to the enhancement of heat transfer rate are represented by increasing the concentration of nanoparticles (Al2O3) volume fraction such as (?=0.1) is better than (?=0, ?=0.05), increasing heat flux such as (16.8W) is better than (7.4W,11W) and an inclination angle such as( 45?) is better than (90?).At the transient state the time to reach to the steady state decreases when the concentration of the nanoparticles (Al2O3) volume fraction increases, the heat flux increases and the angle incline. In model 4 the heat transfer enhancement is better than that of model 3 and model 3 is better than that of model 2 and model 2 is better than that of model 1.The time to reach the steady state decreases in model 4 more than model 3, model 2 and model 1. The temperature decreases in the heat pipe when we gradually sidle from heater. The time to reach to steady state found in model 4 at concentration of nanofluid (?=0.1) and heat flux (16.8W) in angle (45?) is (19 min). In the steady state when we increase the concentration of the nanoparticles (Al2O3) volume fraction at the same distance (z) the temperature increases ,The increase in the heat flux of the hot part of the heat pipe will always increase the temperature in the heat pipe and the temperatures distribution in the heat pipe will be improved. The thermal performance of the heat pipe is enhanced by increasing the concentration of the nanofluid , the heat flux and by inclining the heat pipe from 90? angle to 45? angle such as in result of model 4.

الصفحات الاولى:

مكان الجامعة: بابل

اللغة: الانكليزية

الجامعة: جامعة بابل - كلية الهندسة - قسم الهندسة الكيمياوية

الدرجة: ماجستير

الموضوع الدقيق: الهندسة الكهروكيمياوية

السنة: 2017

الموضوع العام: الهندسة الكيمياوية

اسم المشرف: تحسين علي الحطاب

اسم المؤلف: شهد فالح حسن