Effect of surface roughness on the mass flow rate predictions for adiabatic capillary tubes

Rocha, Thiago Torres Martins; Paula, Cleison Henrique de; Cangussu, Vinícius Melo; Maia, Antônio Augusto Torres; Oliveira, Raphael Nunes de

doi:10.1016/j.ijrefrig.2020.05.020

Cited by 11 publications

(6 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A universal threshold had been proposed to subdivide the flow into smooth and rough microchannels, and new correlations for predicting friction coefficient and critical Reynolds numbers were obtained. Thiago et al [ 75 ] investigated the effect of surface roughness on the mass flow rate inside adiabatic capillaries through experiments. Mandev et al [ 42 ] experimentally studied the influence of surface roughness induced by the manufacturing process on mixed convective heat transfer in microchannels (300–700 μm).…”

Section: Flow and Heat Transfer Mechanism Of Single-phase Fluid Under...mentioning

confidence: 99%

A Review of the Complex Flow and Heat Transfer Characteristics in Microchannels

Zhang

Zou

2023

Micromachines

View full text Add to dashboard Cite

Continuously improving heat transfer efficiency is one of the important goals in the field of energy. Compact heat exchangers characterized by microscale flow and heat transfer have successfully provided solutions for this purpose. However, as the characteristic scale of the channels decreases, the flow and heat transfer characteristics may differ from those at the conventional scale. When considering the influence of scale effects and changes in special fluid properties, the flow and heat transfer process becomes more complex. The conclusions of the relevant studies have not been unified, and there are even disagreements on some aspects. Therefore, further research is needed to obtain a sufficient understanding of flow structure and heat transfer mechanisms in microchannels. This article systematically reviews the research about microscale flow and heat transfer, focusing on the flow and heat transfer mechanisms in microchannels, which is elaborated in the following two perspectives: one is the microscale single-phase flow and heat transfer that only considers the influence of scale effects, the other is the special heat transfer phenomena brought about by the coupling of microscale flow with special fluids (fluid with phase change (pseudophase change)). The microscale flow and heat transfer mechanisms under the influence of multiple factors, including scale effects (such as rarefaction, surface roughness, axial heat conduction, and compressibility) and special fluids, are investigated, which can meet the specific needs for the design of various microscale heat exchangers.

show abstract

Section: Flow and Heat Transfer Mechanism Of Single-phase Fluid Under...mentioning

confidence: 99%

A Review of the Complex Flow and Heat Transfer Characteristics in Microchannels

Zhang

Zou

2023

Micromachines

View full text Add to dashboard Cite

show abstract

“…Rocha et al [7] investigated the effect of surface roughness on the mass flow rate through adiabatic capillary tubes. Experimental measurements were conducted on two different capillary tubes, using a few roughness parameters.…”

Section: Literature Reviewmentioning

confidence: 99%

Capillary Tube Length and Heat Transfer Dynamics in Air Conditioners: A Comparative Analysis of R-12 and Its Alternatives

Mohammed Ali,

Resen,

Ibrahim

2023

IJHT

View full text Add to dashboard Cite

Refrigerant R12, or Freon 12, has been a predominant choice in various refrigeration and air conditioning applications due to its versatility across a broad spectrum of operating conditions. However, R12, a chlorofluorocarbon (CFC) with the chemical formula CCl2F2, poses a significant threat to the ozone layer, contributing to the greenhouse effect. Consequently, the phasing out of R12 is imperative. This study explores viable alternatives to R12, focusing on the impact of external temperature and other parameters on capillary tube length. A detailed comparison between refrigerant R-134a and R-12 is conducted using Engineering Equation Solver (EES) software at Q=366.5 W, d= 1.2 mm, Tconf =45℃ and tsurr=35℃. The software utilizes refrigerant thermodynamic and transport properties, including dynamic viscosity, density, thermal conductivity, and specific enthalpy, in the analysis. The research is aimed at understanding the flow dynamics in a capillary tube based on a model that aligns with the requirements of contemporary refrigerator design. Parameters such as operating conditions and tube diameter are scrutinized, with an emphasis on the direct relationship between them. The study also investigates the performance variability of the two refrigerants under identical conditions. A key finding is the superior quality of R-134a over R-12 in the two-phase region, coupled with the observation that the capillary tube length for R-134a is approximately 20% shorter than that for R-12. These results underscore the intricate relationship between refrigerant type, capillary tube dimensions, and overall system efficiency, thereby informing the design and optimization of next-generation refrigeration systems.

show abstract

“…Yüzey pürüzlülüğünü değiştirmenin etkisinin CO2 için R600a'ya göre yaklaşık 2.5 kat daha belirgin olduğunu söylemişlerdir. Her iki soğutucu için de kütle akış hızının, düz kapiler tüp için sarmal tüpe göre biraz daha fazla olduğunu vurgulamışlardır [2]. Transkritik CO2 ısı pompalı bir su ısıtıcısında dahili eşanjörün etkisi Cao ve ark.…”

Section: Introductionunclassified

Co2 Soğutucu Akişkani İle Çalişan Transkri̇ti̇k Bi̇r Isi Pompasi Si̇stemi̇ni̇n Farkli Basinçlarda Termodi̇nami̇k Anali̇zi̇

ELBİR¹,

Bayrakçı²,

Özgür³

et al. 2022

Teknik Bilimler Dergisi

View full text Add to dashboard Cite

ÖzTranskritik bir çalışma sisteminin deneysel olarak çalışılması sonucunda alınan sonuçlar sunulmuştur. Tek kademeli olarak ve basınç değerleri önceki çalışmalara göre daha da arttırılarak çalıştırılmıştır; 75 bar gaz soğutucu basıncının 100 bar gaz soğutucu basıncına çıkarıldığında ve sudan suya soğutma sağlayan suyun kütlesel debisini artırılması ile aynı sistemde deney sonuçlarının termodinamik kurallara göre nasıl değişeceği ve hangi unsurlarla değişim göstereceği grafiklerle ve resimler ile sunulmuştur. Birinci deneyde 75 bar gaz soğutucu basıncında, ikinci sistemde 100 bar gaz soğutucu basıncında çalıştırılarak adlandırılmıştır. Gaz soğutucu basıncının %33, buna karşılık evaporatör basıncının da %57 artması ile sistemde değişimler incelenmiştir. COPıstm değerine %148 bir artış getirmiş, toplam ekserji kaybı % 3.2 artmış ve kütlesel su soğutma debisi %100 artmıştır. Vanadaki basınç değişimleri ekserji verimini %10,3 arttırmıştır. Soğutucu akışkan kütlesindeki %95,2'lik artış kompresörün elektirik tüketimini %24,4 arttırmıştır. Kompresörün izentropik verimi ve kılcal borunun ekserji verimi basıncın artması ile %10 artmıştır.

show abstract

Effect of surface roughness on the mass flow rate predictions for adiabatic capillary tubes

Cited by 11 publications

References 32 publications

A Review of the Complex Flow and Heat Transfer Characteristics in Microchannels

A Review of the Complex Flow and Heat Transfer Characteristics in Microchannels

Capillary Tube Length and Heat Transfer Dynamics in Air Conditioners: A Comparative Analysis of R-12 and Its Alternatives

Co2 Soğutucu Akişkani İle Çalişan Transkri̇ti̇k Bi̇r Isi Pompasi Si̇stemi̇ni̇n Farkli Basinçlarda Termodi̇nami̇k Anali̇zi̇

Contact Info

Product

Resources

About