Experimental study on instability of round nanofluid jets at low velocity

Shi, Weidong; Li, Fengyu; Lin, Qizhao; Fang, Guofeng; Chen, Liang; Zhang, Liang

doi:10.1016/j.expthermflusci.2020.110253

Cited by 10 publications

(4 citation statements)

References 28 publications

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“…In addition, they determined that the distances and nanoparticle concentration, which affect the flow structure, also affect the Nu together with the Re. Shi et al (2021) experimentally investigated the effects of nano-aluminium additives on the instability of round water jets. Flow visualization in and near the exit of two transparent nozzles was obtained by high-speed shadow imaging technique and it was determined that the effects of nanoparticle additives on jet instability were mainly caused by viscosity increase and cavitation promotion.…”

Section: Introductionmentioning

confidence: 99%

“…Numerical research was carried out by solving steady and three-dimensional energy and Navier-Stokes equations using the Ansys-Fluent program with the k-ε turbulence model. While the lower and upper surfaces of the fin and channel are adiabatic, the model surfaces have a constant heat flux of 1000 W/m 2 , which is also applied in the literature (Shi et al, 2021;Kilic et al, 2017;Karabulut, 2019;Alnak et al, 2021). As it is known, overheating occurs under the intense working load of electronic elements.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Heat Transfer Improvements of Graphene Oxide-Water and Diamond-Water Nanofluids in Cross-Flow-Impinging Jet Flow Channels Having Fin

Karabulut

2023

Isı Bilimi Ve Tekniği Dergisi

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In this study, the heat transfer from two different model surfaces (roof and crown) and flow structure in the channels with the cross flow-impinging jet flow were numerically analyzed by using water, 0.02% GO (Graphene Oxide)-Water and 2% Diamond-Water nanofluids. The numerical study was carried out steady and three dimensional using the Ansys-Fluent program with k-ε turbulence model. A fin with 90o angle was added on the upper channel surface from the impinging jet inlet at distinct distances. A constant heat flux of 1000 W/m2 was applied to the model surfaces. The channel heights are fixed and the Re range of the fluids is 5000-15000. The numerical results obtained from the study were compared with the results of the experimental studies in the literature and it was seen that the results were compatible and acceptable. The results of the study were comparatively examined for water and nanofluids as the mean Nu and surface temperature variations for each model in the channels without fins and at different fin distances. Also, velocity and temperature contour distributions of the combined jet Diamond-Water nanofluid flow were visualized. However, performance coefficient (C) and mean Nu (Num) and, surface temperature values (Tm) were evaluated for all three patterned surfaces in the channels. Num increases for GO-Water nanofluid at Re=15000 and fin distance of 2D are 47.53% and 57.42% compared to the case of using finless and water fluid for the roof and crown model surfaces, respectively.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation of Heat Transfer Improvements of Graphene Oxide-Water and Diamond-Water Nanofluids in Cross-Flow-Impinging Jet Flow Channels Having Fin

Karabulut

2023

Isı Bilimi Ve Tekniği Dergisi

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“…Results showed that the greater Nu was achieved on the straight plate than the ribbed plate. Shi et al 39 have experimentally examined the influence of nano-alumina additives on circular jets' instability at low speed. Shirvani et al 40 numerically assessed the effect of nanoparticle forms on the impingement jet’s heat transfer and flow characteristics.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigations of heat transfer around a hot block subject to a cross-flow and an extended jet hole using ternary hybrid nanofluids

Boudraa

Bessaïh

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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In the last few years, modern heat transfer technologies significantly improved to provide more efficient systems in industries. One of those technologies is cooling electronic components in laminar flow using water nanofluids, which is interesting. This research used a ternary hybrid nanofluid with various nanoparticle forms to conduct a numerical investigation of three-dimensional heat transfer and fluid flow over a heated block exposed to a horizontal flow and an impinging jet. The effects of several variables such as the Reynolds number ratio [Formula: see text], volume fraction of nanoparticles [Formula: see text], length of extended jet hole [Formula: see text], and the influence of the inclination angle of the impinging jet inlet [Formula: see text] on the fluid flow and heat transfer were examined. Using the Ansys-Fluent 14.5 program and under laminar flow conditions, the finite-volume method was applied with the help of the SIMPLE algorithm to solve continuity, momentum, and energy equations. Several characteristics are assessed, including velocity streamline, isotherm contours, Nusselt number contours, the average Nusselt number ([Formula: see text]), the friction factor [Formula: see text], and drop pressure [Formula: see text]. The findings of the current analysis revealed that adding an impinging jet can boost the heat transfer rate up to [Formula: see text] better than a non-impingement jet. Also, a significant enhancement in the heat transfer rate was obtained when growing one of these parameters α, [Formula: see text], and E. Moreover, the ternary hybrid nanofluid with different nanoparticle forms significantly boosts the heat transfer rate compared to the traditional nanofluid. The maximum heat transfer is reached as the velocity of the impinging jet rises. Inclining the angle of the impinging jet inlet with [Formula: see text] toward the channel inlet boosted the rate of heat transfer up to [Formula: see text] compared to the perpendicular impinging jet [Formula: see text]. A strong consensus has been reached with the theoretical and experimental findings found in the literature.

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“…Ayrıca, mesafelerin ve akış yapısını etkileyen nanoparçacık konsantrasyonunun da Re sayısıyla birlikte Nu sayısını etkilediğini belirlemişlerdir. Shi ve ark., [15] nano-alüminyum katkı maddelerinin yuvarlak su jetlerinin kararsızlığı üzerindeki etkilerini deneysel olarak incelemişlerdir. İki şeffaf lülenin içinde ve çıkışının yakınında akış görselleştirmesi, yüksek hızlı gölge görüntüleme tekniği ile elde edilmiş ve nanoparçacık katkı maddelerinin jet kararsızlığı üzerindeki etkilerine esas olarak, viskozite artışı ve kavitasyon teşvikinin neden olduğu belirlenmiştir.…”

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Evaluation of Heat Transfer and Flow Structures in Combined Jet Flow Channels with Copper Oxide-Water and Diamond-Water

KARABULUT

2024

Düzce Üniversitesi Bilim Ve Teknoloji Dergisi

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Bu çalışmada, sabit 1000 W/m2 ısı akısına sahip dairesel oyuklu ve yamuk modelli bakır plakalı yüzeylerden olan ısı transferi ve birleşik jet akışlı kanallardaki akış yapıları su, %2 hacimsel konsantrasyonlu CuO-Su (Bakır oksit)-Su ve Elmas-Su nanoakışkanları kullanılarak sayısal olarak incelenmiştir. Sayısal çalışma, sürekli ve üç boyutlu olarak k-ε türbülans modelli Ansys-Fluent programının kullanılmasıyla gerçekleştirilmiştir. Kanallara ayrıca jet girişinden itibaren D jet giriş çapı ölçüsündeki sabit bir uzaklıkta (N) 45o ve 90o açılı kanatçıklar eklenmiştir. Kanal yüksekliği 3D iken; akışkanların Re sayısı aralığı 5000-15000’ dir. Çalışmadan elde edilen sonuçların doğruluğu ve kabul edilebilirliği deneysel araştırmalar sonucu elde edilen eşitlik kullanılarak kanıtlanmıştır. Çalışmanın sonuçları, kanallardaki her bir model için ortalama Nu sayısının değişimleri olarak su ve nanoakışkanlar için kanatçıksız ve kanatçıklı durumlarda karşılaştırmalı olarak değerlendirilmiştir. Ayrıca, CuO-Su nanoakışkanı için birleşik jet akışın hız ve sıcaklık konturu dağılımları farklı kanatçık açıları için sunulmuştur. Bununla birlikte, kanallardaki her üç desenli yüzeyin tümü için farklı Reynolds sayılarında performans değerlendirme sayıları (PEC) ve ortalama Nu sayısı (Num) ve yüzey sıcaklık değerleri (Tm) Re=5000 ve 15000 için analiz edilmiştir. Re=15000 için 90o kanatçıklı kanalda yamuk modelli yüzeyde sırasıyla Elmas-Su ve Bakır oksit-Su nanoakışkanları kullanılması durumları için kanatçıksız ve su akışkanı kullanılan kanallara göre Num sayısında %27,57 ve %26,11’ lik artışlar elde edilmiştir. Bunun yanı sıra, Re=15000 değerinde 90o açılı kanatçıklı kanallarda su akışkanı için PEC sayısı değerlerinin sırasıyla dairesel oyuklu ve yamuk modelli yüzeylerde Elmas-Su ve CuO-Su nanoakışkanlarına göre %1,1-%1,31 ve %0,82-%0,63 daha fazla oldukları tespit edilmiştir.

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Experimental study on instability of round nanofluid jets at low velocity

Cited by 10 publications

References 28 publications

Investigation of Heat Transfer Improvements of Graphene Oxide-Water and Diamond-Water Nanofluids in Cross-Flow-Impinging Jet Flow Channels Having Fin

Investigation of Heat Transfer Improvements of Graphene Oxide-Water and Diamond-Water Nanofluids in Cross-Flow-Impinging Jet Flow Channels Having Fin

Numerical investigations of heat transfer around a hot block subject to a cross-flow and an extended jet hole using ternary hybrid nanofluids

Evaluation of Heat Transfer and Flow Structures in Combined Jet Flow Channels with Copper Oxide-Water and Diamond-Water

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