Liquid nitrogen boiling around a temperature controlled heated wire

Experimental Study of Boiling Phenomena of Liquid Nitrogen Around a Thin Wire Heater in Open Bath and Inside Capillary Tubes

“…As the heat flux decreases to a certain value, the film boiling state disappears and the superheat also decreases, the boiling state recovers to point G, minimal heat flux (MHF). CHF and MHF are about 12 and 10 W/cm 2 , respectively, which agrees quite well with the results of Dulue et al [1].…”

“…In the nucleate boiling section BC and GH, it is observed that the diameter of the vapor bubble is around 0.5 mm, and the number and departure frequency of the vapor bubbles increase with the heat flux. The experimental exponents m in the nucleate boiling regime BC and GH are about 2.6 and 3.0, respectively, which agrees with the results (m " [2.5, 3.5]) of Dulue et al [1]. It is also found that there is a small negative slope region in BC section, which corresponded to the coalescence of the neighboring vapor bubbles into bigger ones.…”

“…And it is observed that the wavelength of the liquid-vapor interface varies with the inclination angle. The wavelength is between 1.0 and 1.5 mm when the thin wire heater is horizontally placed, which agrees well with the results of Dulue et al [1]. As the inclination angle increases, the wavelength also increases to about 2.5 mm at 30 and 6.7 mm at 60 , while no obvious wavelength can be found at 90 .…”

“…In such cases, good heat transfer performance should be maintained to ensure the stable working condition of the cooled devices, and possible heat transfer enhancement measures should be taken to guarantee the surplus cooling capacity, which requires that the heat transfer characteristics of liquid nitrogen should be well understood. Duluc et al [1] measured the heat transfer performance of a temperature-controlled thin wire heater of 32 mm in diameter in the open liquid nitrogen bath and the heat transfer curve was obtained. They also found that the liquid-vapor interface of the vapor film around the thin wire heater did not follow the typical sine type and the thickness of the vapor film around the thin wire heater was very thin.…”

Experimental Investigation of the Heat Transfer Characteristics of Liquid Nitrogen in the Capillary Tubes

“…In such cases, good heat transfer performance should be maintained in order to keep the stable working condition of the devices, which requires that the heat transfer characteristics of liquid nitrogen should be well understood and possible heat transfer enhancement methods should be taken. M. C. Duluc [1] measured the heat transfer performance of a temperature-controlled thin wire heater in the open liquid nitrogen bath and the heat transfer curves up to film boiling regime were obtained. H. Kubota et al [2] studied the heat transfer of liquid nitrogen in a horizontally placed capillary tube and the subcooling effect of liquid nitrogen on the heat transfer performance was investigated.…”