Limits...
Measurement of local two-phase flow parameters of nanofluids using conductivity double-sensor probe.

Park YS, Chang SH - Nanoscale Res Lett (2011)

Bottom Line: The void fraction, interfacial velocity, interfacial area concentration, and mean bubble diameter were evaluated, and all of those results using the nanofluid were compared with the corresponding results for pure water.The higher interfacial area concentration resulted in a smaller mean bubble diameter in the case of the nanofluid.Throughout this experimental study, the differences in the internal two-phase flow structure of the nanofluid were identified.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nuclear and Quantum Engineering, KAIST, 335 Gwahak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea. yusunpark@kaist.ac.kr.

ABSTRACT
A two-phase flow experiment using air and water-based γ-Al2O3 nanofluid was conducted to observe the basic hydraulic phenomenon of nanofluids. The local two-phase flow parameters were measured with a conductivity double-sensor two-phase void meter. The void fraction, interfacial velocity, interfacial area concentration, and mean bubble diameter were evaluated, and all of those results using the nanofluid were compared with the corresponding results for pure water. The void fraction distribution was flattened in the nanofluid case more than it was in the pure water case. The higher interfacial area concentration resulted in a smaller mean bubble diameter in the case of the nanofluid. This was the first attempt to measure the local two-phase flow parameters of nanofluids using a conductivity double-sensor two-phase void meter. Throughout this experimental study, the differences in the internal two-phase flow structure of the nanofluid were identified. In addition, the heat transfer enhancement of the nanofluid can be resulted from the increase of the interfacial area concentration which means the available area of the heat and mass transfer.

No MeSH data available.


Related in: MedlinePlus

Mounting the conductivity double-sensor two-phase void meter on the test section.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211349&req=5

Figure 3: Mounting the conductivity double-sensor two-phase void meter on the test section.

Mentions: The conductivity double-sensor two-phase void meter is mounted at a height of 1.75 m from the bottom of the test section as shown in the Figure 3. The position of the L-shape sensor tip in the radial direction is controlled by a micrometer attached onto the sensor. The output voltage of two-phase identification signal is obtained for 2 s at a 50-kHz sampling frequency. Three times of measurement were conducted at a total of 15 points from the center to the tube inner wall, and the averaged value at each point was used for the analysis. In this study, the same type of a conductivity double-sensor two-phase void meter which was used by Walter [3] was installed and the measurement uncertainty of the void meter is estimated to have a maximum value of 10.5%.


Measurement of local two-phase flow parameters of nanofluids using conductivity double-sensor probe.

Park YS, Chang SH - Nanoscale Res Lett (2011)

Mounting the conductivity double-sensor two-phase void meter on the test section.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211349&req=5

Figure 3: Mounting the conductivity double-sensor two-phase void meter on the test section.
Mentions: The conductivity double-sensor two-phase void meter is mounted at a height of 1.75 m from the bottom of the test section as shown in the Figure 3. The position of the L-shape sensor tip in the radial direction is controlled by a micrometer attached onto the sensor. The output voltage of two-phase identification signal is obtained for 2 s at a 50-kHz sampling frequency. Three times of measurement were conducted at a total of 15 points from the center to the tube inner wall, and the averaged value at each point was used for the analysis. In this study, the same type of a conductivity double-sensor two-phase void meter which was used by Walter [3] was installed and the measurement uncertainty of the void meter is estimated to have a maximum value of 10.5%.

Bottom Line: The void fraction, interfacial velocity, interfacial area concentration, and mean bubble diameter were evaluated, and all of those results using the nanofluid were compared with the corresponding results for pure water.The higher interfacial area concentration resulted in a smaller mean bubble diameter in the case of the nanofluid.Throughout this experimental study, the differences in the internal two-phase flow structure of the nanofluid were identified.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nuclear and Quantum Engineering, KAIST, 335 Gwahak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea. yusunpark@kaist.ac.kr.

ABSTRACT
A two-phase flow experiment using air and water-based γ-Al2O3 nanofluid was conducted to observe the basic hydraulic phenomenon of nanofluids. The local two-phase flow parameters were measured with a conductivity double-sensor two-phase void meter. The void fraction, interfacial velocity, interfacial area concentration, and mean bubble diameter were evaluated, and all of those results using the nanofluid were compared with the corresponding results for pure water. The void fraction distribution was flattened in the nanofluid case more than it was in the pure water case. The higher interfacial area concentration resulted in a smaller mean bubble diameter in the case of the nanofluid. This was the first attempt to measure the local two-phase flow parameters of nanofluids using a conductivity double-sensor two-phase void meter. Throughout this experimental study, the differences in the internal two-phase flow structure of the nanofluid were identified. In addition, the heat transfer enhancement of the nanofluid can be resulted from the increase of the interfacial area concentration which means the available area of the heat and mass transfer.

No MeSH data available.


Related in: MedlinePlus