scholarly journals An evaluation of phase change microcapsules for use in enhanced heat transfer fluids

1991 ◽  
Vol 18 (4) ◽  
pp. 495-507 ◽  
Author(s):  
Sanjay K. Roy ◽  
S. Sengupta
2013 ◽  
Vol 372 ◽  
pp. 143-148 ◽  
Author(s):  
Suhaib Umer Ilyas ◽  
Rajashekhar Pendyala ◽  
Narahari Marneni

Nanofluids are considered as promising heat transfer fluids due to enhanced heat transfer ability as compared to the base fluid alone. Knowledge of settling characteristics of nanofluids has great importance towards stability of nanosuspensions. Sedimentation behavior of Alumina nanoparticles due to gravity has been investigated using different proportions of ethanol-water binary mixtures. Nanoparticles of 40 nm and 50 nm are used in this investigation at 23°C. Sediment height with respect to time is measured by visualization method in batch sedimentation. The effect of sonication on the sedimentation behavior is also studied using ultrasonic agitator. The effect of particle diameter, nanoparticle concentration and ethanol-water proportion on sedimentation behavior of nanofluids has been investigated and discussed.


Author(s):  
Miad Yazdani ◽  
Jamal Seyed-Yagoobi

Electrohydrodynamic (EHD) conduction pumping is associated with the heterocharge layers of finite thickness in the vicinity of the electrodes, generated by the process of dissociation of the neutral electrolytic species and recombination of the generated ions. This paper numerically investigates the EHD conduction pumping of a thin liquid film in the presence of phase change. The flow system comprises a liquid film flowing over a two-dimensional flat plate while the vapor phase extended far beyond the interface to result in almost motionless vapor. The channel is separated into four different sections: the entrance, electrode, evaporation, and downstream sections. The entrance, electrode and downstream regions are adiabatic while a constant heat flux is applied in the evaporation side. The concept of EHD conduction pumping of liquid film in the presence of phase change is demonstrated in this paper. The enhanced heat transfer due to conduction pumping is evaluated.


2016 ◽  
Vol 745 ◽  
pp. 032133 ◽  
Author(s):  
L J Fischer ◽  
S von Arx ◽  
U Wechsler ◽  
S Züst ◽  
J Worlitschek

Author(s):  
Nikhil Dhiman ◽  
Jeet Shah ◽  
Dereje Agonafer ◽  
Naveen Kannan ◽  
James Hoverson ◽  
...  

The ever increasing information technology heat load and data center cooling energy are the main reasons to investigate the performance of microencapsulated phase change slurry over other heat transfer fluids. Microencapsulated phase change slurry is dispersion where the phase change material, microencapsulated by a polymeric capsule, is dispersed in water. Compared to water, these new fluids have a higher heat capacity during phase change and a possible enhancement, as a result of this phase change, in the heat transfer phenomenon. The composition of phase change material used in slurry greatly affects its efficiency, If not selected properly it can cause serious damage, e.g. agglomeration and clogging of pipes. The main objective of this work is to develop standalone pumpable microencapsulated phase change slurry that is able to withstand shear stresses of the pump and other course surfaces of pipe and pipe joints. In this study, experiments were performed, to determine performance of microencapsulated phase change slurry over conventional heat transfer fluids. After certain pumping cycles, scanning electron microscopy (SEM) has been done to analyze the conditions of shell material of polymeric capsule. Results obtained from SEM show that centrifugal pump is compatible with mPCM particle size upto 3 μm. It is true that selected mPCS have shown better performance over water in hot water bath in case of thermal storage. Also, closed loop final testing has shown that heat flux is about 2–3 times higher with mPCS than water.


2019 ◽  
Vol 92 (3) ◽  
pp. 285-301 ◽  
Author(s):  
Wei Li ◽  
Yan Dong ◽  
Jun Wang ◽  
Yong Zhang ◽  
Xu Zhang ◽  
...  

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