بررسی عملکرد فن‌های کندانسور سیستم سرمایشی در سرعت‌های مختلف قطار شهری

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده فنی و مهندسی، دانشگاه حکیم سبزواری، سبزوار، ایران

چکیده

در مطالعه حضر رفتار سیال به منظور ارزیابی اثرات جریان مخالف ناشی از حرکت قطار بر عملکرد فن‌های کندانسور سامانه سرمایشی مورد بررسی قرار می‌گیرد. در سرعت‌های مختلف قطار، پروفیل منحنی سرعت جریان خروجی از فن و همچنین تغییرات دمایی در محدوده فن مورد بررسی قرار گرفتند. در تحلیل عددی، معادلات ناویر استوکس و انرژی برای جریان درهم و تراکم ناپذیر و مدل توربولانسی k-ε نیز برای مدل سازی جریان درهم استفاده شده‌اند. نتایج به صورت تغییرات دما در محدوده فن، سرعت جریان فن و طول مؤثر که به عنوان معیاری برای میزان هدایت جریان خروجی از فن در خلاف جهت حرکت قطار می‌باشد در سرعت‌های مختلف قطار شهری گزارش شده‌اند. در سرعت‌های بالای قطار، سرعت منفی در فن و افزایش طول موثرمؤثر مشاهده شده اند. در حداکثر سرعت قطار، طول مؤثر بدون بعد در ارتفاع 10 و 20 سانتی متری به مقدار 528/0 و 952/0 می رسد. در انتها نیز پارامتری که بیانگر نسبت نرخ حرارتی به نرخ حرارتی ماکزیمم بیشینه می‌باشد در ارتفاع 10 سانتی متری تعریف می‌شود که مقدار آن در حداکثر سرعت قطار 88/5 درصد می‌باشد که دلیل کاهش این پارامتر غالب شدن جریان مخالف بر جریان فن بوده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation of the Cooling System Condenser Fans Performance at Different Speeds of Subway Train

نویسندگان [English]

  • R. Nazeri Boori Abadi
  • N. Rezazadeh
  • M. Deymi-Dashtebayaz
Department of Mechanical Engineering, Hakim Sabzevari University, Sabzevar, Iran
چکیده [English]

In the present work to evaluate the cross wind flow effects due to the subway train motion on efficiency of condenser fans in air conditioning system, the behavior of fluid have been studied. Velocity profiles in output fan, temperature variations at near fan were studied at different velocity of train. In numerical analysis, for the turbulent and incompressible flow, Navier-Stokes and energy equations and k‑ε turbulence model has been used for modeling of turbulent flow. Variations of temperature and velocity of outflow of the fan at horizontal and vertical directions and the effective length as outflow guidance of the fan in opposite direction of train at difference velocity of train have been reported. At high velocity of train, negative output velocity of the fan and high effective length have been observed. Dimensionless effective length in high velocity of train at height of 10 and 20 cm were obtained 0.528 and 0.951 respectively. Finally, a parameter that is heat transfer rate to maximum heat transfer rate at height of 10 cm is defined which maximum amount is 5.88 percent. Due to the prevailing crosswind flow on the outflow of the fan, this parameter reduces.

کلیدواژه‌ها [English]

  • Cross wind flow
  • Air conditioning system
  • Condenser
  • variation of temperature and velocity
  • Heat capacity
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