1990 Fiscal Year Final Research Report Summary
Microscopic Study of Scalings on Heat Transfer Surfaces
| Project/Area Number |
01460114
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thermal engineering
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| Research Institution | Hokkaido University |
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Principal Investigator |
ISHIGURO Ryoji Hokkaido Univ., Fac. of Eng., Professor, 工学部, 教授 (20001167)
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| Co-Investigator(Kenkyū-buntansha) |
SUGIYAMA Ken-ichiro Hokkaido Univ., Fac. of Eng., Associate Professor, 工学部, 助教授 (10002015)
SAKASHITA Hiroko Hokkaido Univ., Fac. of Eng., Research Associate, 工学部, 助手 (00142696)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Heat Exchanger / Forced Convection / Nucleation / Fouling / Scaling / Calcium Carbonate / Crystal Growth |
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| Research Abstract |
For the purpose of obtaining the essential information of scaling in heat exchangers, microscopic observations were made for CaCO_3 deposition from flowing solution onto initially clean heat transfer surfaces. The growing rates of CaCO_3 crystals were measured by changing Reyno lds number and supersaturation degree of bulk solution, material and temperature of the heat transfer surface. The growing rate was found to be relatively well correlated by the supersaturation degrees of solution adjacent to the surface, deduced from the equilibrium relationship between the species in the carbonic solution. The nucleation rate was also estimated by measuring the change of cumulative number density of deposited crystals against time. The crystals were formed on the surface with constant nucleation rate over time, but the factors, which dominate the nucleation rate, could not be determined.
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