The measurement of the surface tension of molten Fe-3.52 Pct C-2.02 Pct Si (-Al, -Ti, -N) alloys by the maximum bubble p
- PDF / 429,722 Bytes
- 4 Pages / 603.28 x 783.28 pts Page_size
- 33 Downloads / 145 Views
REFERENCES 1. T.F. Irvine, Jr. and J.P. Hartnett: Advances in Heat Transfer, Academic Press, New York, NY, 1966, vol. 3, pp. 102-72. 2. S. Glasstone: Principles of Nuclear Reactor Engineering, 1st ed., Norstand Company, New York, NY, 1955, ch. 10. 3. A.K. Mohanty and S.B.L. Asthana: J. Fluid Mech., 1979, vol. 90, pp. 433-47. 4. W.M. Kays: Convective Heat and Mass Transfer, McGraw-Hill, New York, NY, ch. 8, 1975.
NOMENCLATURE Nux
Nu F
R Re
Tm To Tref Tw T= u0 x
Y
local Nusselt number average Nusselt number radial coordinate, m radius of the circular duct, m Reynolds number, 2 U o R / u mixed mean temperature, K fluid temperature at inlet, K (Tw - To) for UWT and q w R / k for UHF duct wall temperature, K centerline temperature, K nondimensional axial velocity inlet velocity, m / s axial coordinate, m transverse coordinate, m
Greek Symbols 6 6,
hydrodynamic boundary layer thickness, m, 6~ = 6 / R thermal boundary layer thickness, m, 6,, =
a,/R ~7~ 0
dimensionless transverse distance (thermal), Y/6t or y / R nondimensional temperature profile, ( T - T=)I(Tw T=) (Tw - T)/(Tw - Tm) nondimensional centerline temperature, (T~ - To)/Tre f kinematic viscosity, m2/s nondimensional axial distance, x / ( R . Re) -
Om y
u sc
The Measurement of the Surface Tension of Molten Fe-3.52 Pct C-2.02 Pct Si (-AI,-Ti,-N) Alloys by the Maximum Bubble Pressure Method NOBUAKI OHARA and EIICHI KATO The surface tension of molten Fe-3.52 pct C-2.02 pct Si (-A1,-Ti,-N) alloys has been measured by the 200--VOLUME 24B, FEBRUARY 1993
maximum bubble pressure method for the purpose of clarifying the effects of A1, Ti, and N on the formation of hydrogen blowholes in cast iron. Many researchers have reported the effects of A1 and Ti on the hydrogen blowhole susceptibility in cast iron. For example, Dawson and Smith t~] and Ohara and Kato [2,3] reported that the addition of either A1 or Ti did not increase the hydrogen blowhole susceptibility. On the other hand, these researchers also reported that the hydrogen blowhole susceptibility was increased in gray iron containing both 0.05 to - 0 . 1 2 pct A1 and 0.1 pct Ti. Hernandez and Wallece [4] measured the surface tension of the melts containing A1 or Ti and also other elements by the maximum bubble pressure method and conducted the casting experiments of the pinhole test plates for the purpose of investigating the relation between the surface tension and the hydrogen pinhole susceptibility. They reported that the correlation between the surface tension measured by the use of a high-purity argon gas and the pinhole susceptibility was generally good. Turkdogan TM suggested that the effects of A1 and Ti on the surface tension might be attributed to the interaction of the dissolved elements (AI, Ti) and nitrogen in air-melted cast iron and that there was the possibility of lowering of the surface tension due to nitrogen-induced AI(Ti) chemisorption at the surface of the melts. Turkdogan proposed that the surface tension measurements should be made at controlled contents of nitrogen in the mel
Data Loading...
