سوابق علمی - اجرائی

سوابق تحصیلی

  • ثبت نشده ليسانس

    مهندسی مکانیک در طراحی جامدات

    سيستان وبلوچستان

  • 1381فوق ليسانس

    مهندسی مکانیک تبدیل انرژی

    خواجه نصيرالدين طوسي

  • 1392دکتری تخصصی

    مهندسی مکانیک

    خواجه نصيرالدين طوسي

مراتب علمی

  • مربي1391

    گروه آموزشی مکانیک

  • استاديار1392

    گروه آموزشی مکانیک

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نمایش:

Hybrid heating systems optimization of residential environment to have thermal comfort conditions by numerical simulation

Nabi Jahantigh
ثبت نشده , ثبت نشده , Year : 2015 , Pages: -, ISSN: Journal Paper

Abstract

بررسي عددي عملكرد سيستم تبريد با اجكتور دو مرحله¬اي

نبی جهانتیغ
ثبت نشده ، ثبت نشده ، سال : ثبت نشده ، صفحات : 20-29، شاپا: مقاله در مجله

چکیده

Providing an Analytical Model in Determining Nanofluids

Alireza Shahriari,Nabi Jahantigh,Fateme Rakani
IRAN , International Journal of Engineering , Year : 2017 , Pages: 1919-1924, ISSN:1025-2495 Journal Paper

Abstract

The influence of temperature, mean nanoparticle size and the nanoparticle concentration on the dynamic viscosities of nanofluids are investigated in an analytical method followed by introduction of modified equations for calculating the nanofluids’ viscosities. A new correlation is developed for effective viscosity based on the previous model where the Brownian movement of the nanoparticles is considered as the key mechanism. In previous studies, the proposed models were not appropriate for nanoparticles larger than 36 nm. They were also focused on low concentrations of nanoparticles up to 5%. The possibility of homogeneous dispersion of the nanoparticles and the Stokes law are observed here. This new model is explained in terms of temperature, mean nanoparticle diameter, nanoparticle volume concentration and both the nanoparticle and base fluid thermophysical characteristics for the effective viscosity of nanofluids. A combined correction factor is introduced to take into account the simplification for a free stream boundary condition outside the boundary layer. A good agreement is observed between the effective viscosity obtained in this new model and those of recorded experiments conducted for different nanofluids. The results show that the present model is valid for large volume concentration (0% < φ <11%), mean nanoparticle size (13 nm < dp < 95 nm), temperature variations (290 K <T < 350 K) and various types of nanoparticles.

Assessment of Particle-size and Temperature Effect of Nanofluid on Heat Transfer Adopting Lattice Boltzmann Model

Alireza Shahriari,Nabi Jahantigh,Fateme Rakani
IRAN , International Journal of Engineering , Year : 2018 , Pages: 1749-1759, ISSN:1025-2495 Journal Paper

Abstract

The investigation of the effect of nanoparticles’ mean diameter and temperature of Al2O3–water nanofluid on velocity and energy field using the lattice Boltzmann method is the main objective of this study. The temperature of the vertical walls is considered constant at Tc and Th, respectively, while the up and the down horizontal surfaces are smooth and insulated against heat and mass. The influences of Grashof number (103 , 104 , 105 ) Prandtl number (Pr=3.42, 5.83), the various volume fraction of nanoparticles (φ=0, 0.01, 0.03, 0.05) and particle-size (dp= 24, 47, 100 nm) were carried out on heat transfer and flow fields. It was concluded that addition of nanoparticles causes a significantly affect on temperature and flow fields. The decrement of heat transfer is observed with the increment of solid volume fraction, but it increases when Grashof number and nanoparticles’ mean diameter increase. The decrement of nanoparticles’ mean diameter and Prandtl number have the same effect on Nusselt number. In addition, it was resulted that the thermal conductivity model had insignificantly impact on the mean Nusselt number than the dynamic viscosity model.

بررسي و مقايسه گرمايش جابجايي با گرمايش همزمان جابجايي- تابشي به صورت غير دائم در ساختمان براي ايجادآسايش حرارتي

نبی جهانتیغ
ثبت نشده ، سال : -0001 مقاله کنفرانسی

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  •   پست الکترونیک:njahantigh@uoz.ac.ir