Laminar Heat Transfer Behavior of a Phase Change Material Fluid in Microchannels With Staggered Pins

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Satyanarayana Kondle ◽  
Jorge L. Alvarado ◽  
Charles Marsh
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Phase Change ◽  
Phase Change Material ◽  
Single Phase ◽  
Internal Heat ◽  
Heat Removal ◽  
Heat Transfer Fluid ◽  
Change Material ◽  
Phase Fluid

Microchannels have been studied extensively for a variety of heat transfer applications including electronic cooling. Many configurations of microchannels have been studied and compared for their effectiveness in terms of heat removal. Recently, the use of staggered pins in microchannels has gained considerable traction, since they can promote internal flow fluctuations that enhance internal heat transfer. Furthermore, staggered pins in microchannels have shown higher heat removal characteristics because of the continuous breaking and formation of the heat transfer fluid boundary layer. However, they also exhibit higher pressure drop because the pins act as flow obstructions. This paper presents numerical results of two characteristic staggered 100-μm pins (square and circular) in microchannels. The heat transfer performance of a single phase fluid (SPF) in microchannels with staggered pins, and the corresponding pressure drop characteristics are presented. Furthermore, a phase change material (PCM, n-eicosane) fluid was also considered by implementing the effective specific heat capacity model approach to account for the corresponding phase change process of PCM fluid. Comparisons of the heat transfer characteristics of single phase fluid and PCM fluid are presented for two different pin geometries and three different Reynolds numbers. Circular pins were found to be more effective in terms of heat transfer by exhibiting higher Nusselt number. Microchannels with circular pins were also found to have lower pressure drop compared to the square-pin microchannels.

Laminar Flow Forced Convection Heat Transfer Behavior of Phase Change Material Fluid in Microchannels With Staggered Pins

2010 ◽  
Author(s):  
Satyanarayana Kondle ◽  
Jorge L. Alvarado ◽  
Charles Marsh ◽  
Gurunarayana Ravi
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Phase Change ◽  
Single Phase ◽  
Convection Heat Transfer ◽  
Heat Removal ◽  
High Heat ◽  
High Heat Flux ◽  
Small Areas ◽  
Phase Fluid

Microchannels have been extensively studied for electronic cooling applications ever since they were found to be effective in removing high heat flux from small areas. Many configurations of microchannels have been studied and compared for their effectiveness in heat removal. However, there is little data available in the literature on the use of pins in microchannels. Staggered pins in microchannels have higher heat removal characteristics because of the continuous breaking and formation of the boundary layer, but they also exhibit higher pressure drop because pins act as flow obstructions. This paper presents numerical results of two characteristic staggered pins (square and circular) in microchannels. The heat transfer performance of a single phase fluid in microchannels with staggered pins, and the corresponding pressure drop characteristics are also presented. An effective specific heat capacity model was used to account for the phase change process of PCM fluid. Comparison of heat transfer characteristics of single phase fluid and PCM fluid are made for two pins geometries for three different Reynolds numbers. Circular pins were found to be more effective in terms of heat transfer by exhibiting higher Nusselt number. Circular pin microchannels were also found to have lower pressure drop compared to the square pin microchannels.

Experimental Study on Thermal Characteristics of Finned Coil LHSU Using Paraffin as Phase Change Material

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Guansheng Chen ◽  
Nanshuo Li ◽  
Huanhuan Xiang ◽  
Fan Li
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Phase Change ◽  
Phase Change Material ◽  
Water Flow ◽  
Water Flow Rate ◽  
Thermal Characteristics ◽  
Heat Transfer Fluid ◽  
Latent Heat Storage ◽  
Change Material

It is well known that attaching fins on the tubes surfaces can enhance the heat transfer into and out from the phase change materials (PCMs). This paper presents the results of an experimental study on the thermal characteristics of finned coil latent heat storage unit (LHSU) using paraffin as the phase change material (PCM). The paraffin LHSU is a rectangular cube consists of continuous horizontal multibended tubes attached vertical fins at the pitches of 2.5, 5.0, and 7.5 mm that creates the heat transfer surface. The shell side along with the space around the tubes and fins is filled with the material RT54 allocated to store energy of water, which flows inside the tubes as heat transfer fluid (HTF). The measurement is carried out under four different water flow rates: 1.01, 1.30, 1.50, and 1.70 L/min in the charging and discharging process, respectively. The temperature of paraffin and water, charging and discharging wattage, and heat transfer coefficient are plotted in relation to the working time and water flow rate.

scholarly journals Numerical Simulation of the Impact of the Heat Source Position on Melting of a Nano-Enhanced Phase Change Material

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1425
Author(s):  
Tarek Bouzennada ◽  
Farid Mechighel ◽  
Kaouther Ghachem ◽  
Lioua Kolsi
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Numerical Study ◽  
Melting Rate ◽  
Heat Transfer Fluid ◽  
Commercial Code ◽  
Tube Position ◽  
The Impact ◽  
Change Material

A 2D-symmetric numerical study of a new design of Nano-Enhanced Phase change material (NEPCM)-filled enclosure is presented in this paper. The enclosure is equipped with an inner tube allowing the circulation of the heat transfer fluid (HTF); n-Octadecane is chosen as phase change material (PCM). Comsol-Multiphysics commercial code was used to solve the governing equations. This study has been performed to examine the heat distribution and melting rate under the influence of the inner-tube position and the concentration of the nanoparticles dispersed in the PCM. The inner tube was located at three different vertical positions and the nanoparticle concentration was varied from 0 to 0.06. The results revealed that both heat transfer/melting rates are improved when the inner tube is located at the bottom region of the enclosure and by increasing the concentration of the nanoparticles. The addition of the nanoparticles enhances the heat transfer due to the considerable increase in conductivity. On the other hand, by placing the tube in the bottom area of the enclosure, the liquid PCM gets a wider space, allowing the intensification of the natural convection.

scholarly journals Testing the performance of a prototype thermal energy storage tank working with organic phase change material for space heating application conditions

2019 ◽  
Vol 116 ◽  
pp. 00038 ◽  
Author(s):  
Maria K. Koukou ◽  
Michail Gr. Vrachopoulos ◽  
George Dogkas ◽  
Christos Pagkalos ◽  
Kostas Lymperis ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Finned Tube ◽  
Heat Transfer Fluid ◽  
Outlet Temperature ◽  
Change Material

A prototype Latent Heat Thermal Energy Storage (LHTES) unit has been designed, constructed, and experimentally analysed for its thermal storage performance under different operational conditions considering heating application and exploiting solar and geothermal energy. The system consists of a rectangular tank filled with Phase Change Material (PCM) and a finned tube staggered Heat Exchanger (HE) while water is used as Heat Transfer Fluid (HTF). Different HTF inlet temperatures and flow rates were tested to find out their effects on LHTES performance. Thermal quantities such as HTF outlet temperature, heat transfer rate, stored energy, were evaluated as a function of the conditions studied. Two commercial organic PCMs were tested A44 and A46. Results indicate that A44 is more efficient during the charging period, taking into account the two energy sources, solar and heat pump. During the discharging process, it exhibits higher storage capacity than A46. Concluding, the developed methodology can be applied to study different PCMs and building applications.

Numerical Investigation of Flow and Heat Transfer Performance of Nano-Encapsulated Phase Change Material Slurry in Microchannels

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Sarada Kuravi ◽  
Krishna M. Kota ◽  
Jianhua Du ◽  
Louis C. Chow
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Numerical Investigation ◽  
Phase Change Material ◽  
Temperature Fields ◽  
Heat Transfer Fluid ◽  
Inlet Temperature ◽  
Bulk Fluid ◽  
Encapsulated Phase Change Material ◽  
Change Material

Microchannels are used in applications where large amount of heat is produced. Phase change material (PCM) slurries can be used as a heat transfer fluid in microchannels as they provide increased heat capacity during the melting of phase change material. For the present numerical investigation, performance of a nano-encapsulated phase change material slurry in a manifold microchannel heat sink was analyzed. The slurry was modeled as a bulk fluid with varying specific heat. The temperature field inside the channel wall is solved three dimensionally and is coupled with the three dimensional velocity and temperature fields of the fluid. The model includes the microchannel fin or wall effect, axial conduction along the length of the channel, developing flow of the fluid and not all these features were included in previous numerical investigations. Influence of parameters such as particle concentration, inlet temperature, melting range of the PCM, and heat flux is investigated, and the results are compared with the pure single phase fluid.

Experimental and Numerical Investigation of Heat Transfer Characteristics of Liquid Flow With Micro-Encapsulated Phase Change Material

2008 ◽  
Author(s):  
Rami Sabbah ◽  
Jamal Yagoobi ◽  
Said Al Hallaj
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Pressure Drop ◽  
Phase Change ◽  
Phase Change Material ◽  
Operating Conditions ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Encapsulated Phase Change Material ◽  
Change Material

This experimental and numerical study investigates Micro-Encapsulated Phase Change Material (MEPCM) heat transfer characteristics and corresponding pressure drop. To conduct this study, an experimental setup consisting of a steel tube with an inner diameter of 4.3mm, outer diameter of 6.5mm and a length of 1,016mm is selected. A MEPCM mass concentration of 20% slurry with particle diameter ranging between 5–15μm is included in this study. Tube wall temperature profile, fluid inlet, outlet temperatures, the pressure drop across the tube are measured and corresponding Nusselt number are determined for various operating conditions. The experimental results are used to validate the numerical model predictions. The numerical model results show good agreement with the experimental data under various operating conditions. The controlling parameters are identified and their effects on the heat transfer characteristics of micro-channels with MEPCM slurries are evaluated.

scholarly journals Effect of the phase change material in a solar receiver on thermal performance of parabolic dish collector

2017 ◽  
Vol 21 (6 Part B) ◽  
pp. 2803-2812 ◽  
Author(s):  
Ramalingam Senthil ◽  
Marimuthu Cheralathan
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Exergy Efficiency ◽  
Heat Transfer Fluid ◽  
Solar Radiation Intensity ◽  
Chloride Hexahydrate ◽  
Parabolic Dish ◽  
Solar Receiver ◽  
Change Material

In this work, the use of phase change material in the circular tank solar receiver is proposed for a 16 m2 Scheffler parabolic dish solar concentrator to improve the heat transfer in the receiver. Magnesium chloride hexahydrate with melting temperature of 117?C is selected as the phase change material in the annular space of the receiver with rectangular fins inside the phase change material. Experimental work is carried out to analyze heat transfer from the receiver to heat transfer fluid with and without phase change material in the inner periphery. Energy and exergy efficiency are determined from the measurements of solar radiation intensity, receiver temperature, surroundings temperature, heat transfer fluid inlet and outlet temperatures, storage tank temperature, and wind speed. The experiments were conducted in SRM University, Chennai, India (latitude: 13? 5? N, longitude: 80?16? E) in April 2014. Use of phase change material in receiver periphery increased energy efficiency by 5.62%, exergy efficiency by 12.8% and decreased time to reach the boiling point of water by 20% when compared with the receiver without phase change material.

Sign in / Sign up

Export Citation Format

Share Document