حل تحلیلی دوبعدی انتقال حرارت و جرم و بررسی تولید آنتروپی در فرایند خشک شدن یک‌تکه میوه به شیوه‌ی همرفت

نوع مقاله : مقاله علمی

نویسنده
حسین مجدی عبداله آباد
استادیار، مهندسی مکانیک، دانشگاه ملی مهارت، تهران، ایران
10.22034/stme.2026.550259.1174
چکیده
افزایش بازده انرژی خشک‌کن‌ها نقش مهمی در توسعه­ی صنعت خشک کردن دارد. بدین جهت در این تحقیق، پس از حل تحلیلی دوبعدی توزیع دما و رطوبت در جسم مرطوب، تولید آنتروپی در فرایند خشک کردن به شیوه­ی همرفت به کمک قانون دوم ترمودینامیک بررسی شده است. تولید آنتروپی برای جریان هوا و جسم مرطوب در حال خشک شدن محاسبه گردیده و نقش عواملی هم­چون نسبت ظاهری جسم مرطوب و دما و سرعت جریان هوای ورودی در تولید آنتروپی تحلیل شده است. نتایج نشان می­دهد که نسبت ظاهری کوچک­تر (نسبت ظاهری 4-1ar=) تولید آنتروپی کمتری دارد. هرچه اختلاف دمای هوای ورودی و دمای جسم مرطوب کم­تر شود و سرعت جریان ورودی کاهش یابد، تولید آنتروپی نیز کم می­شود و با بیشتر شدن دما و سرعت جریان، محصول خشک‌شده‌تری به دست می­آید؛ اما با توجه به میزان رطوبت نهایی جسم مرطوب و تولید آنتروپی، یک مقدار بهینه برای دما ) و سرعت جریان هوای ورودی ( ) در نظر گرفته می­شود. افزایش دمای جریان هوا در برابر افزایش سرعت جریان هوا، افزایش تولید آنتروپی بسیار بیشتری را نشان می­دهد. همچنین مشخص می‌شود که جسم مرطوب سهم بیشتری در تولید آنتروپی دارد. 89% آنتروپی در جسم مرطوب و 11% درصد دیگر در جریان تولید می­شود. همچنین در کل سیستم 69% تولید آنتروپی حرارتی است و 39% دیگر تولید آنتروپی ناشی از انتقال جرم می­باشد.
کلیدواژه‌ها
خشک شدن به شیوه ی همرفت
قانون دوم ترمودینامیک
بهینه سازی
انتقال حرارت و انتقال جرم
تولید آنتروپی
موضوعات

عنوان مقاله English

Entropy generation optimization during convective drying of an apple slice

نویسنده English

Hosein Majdi Abdollah Abad
1. Assistant Professor, Department of Mechanical Engineering, Technical and Vocational University (TVU), Tehran, Iran
چکیده English

Development of high energy efficiency dryers is of great importance for the future of the drying industry. The present research studied entropy production in the process of convective drying of an apple slice with the second law of thermodynamics. The entropy production in fluid flow and moist object is computed and influences of aspect ratio of moist object and inlet temperature and velocity of fluid flow on the entropy production are analyzed. The result show that smaller aspect ratio produces less entropy; also by decreasing inlet temperature and velocity of fluid flow, the entropy production decreases too and by increasing inlet temperature and velocity of fluid flow, moist object will be dried sooner. So respect to the amount of entropy production and final moisture content of the moist object, an optimized value for inlet temperature and velocity of fluid flow will be obtained. The effect of inlet temperature increase on the entropy production is more than inlet velocity increase. The study shows that the second law of thermodynamics is a potential tool for optimizing the drying process and dryers designing.

کلیدواژه‌ها English

Convective Drying
Second Law of Thermodynamics
Optimization
Heat and Mass Transfer
Entropy Production
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  • تاریخ دریافت 08 مهر 1404
  • تاریخ بازنگری 13 آذر 1404
  • تاریخ پذیرش 02 اسفند 1404
  • تاریخ اولین انتشار 02 اسفند 1404
  • تاریخ انتشار 01 مرداد 1405