As a vaporizer is a necessary goods which is essential to all-round general and other industries, it plays a role of injecting liquid gas safely to production process by converting the liquid gas to be vaporized to gas.
This paper examines and conducts the experiment regarding outer heat transfer characteristic of ambient air vaporizer which receives the heat through natural convection by using external air. Used fluid is a liquid nitrogen which has lower risk for use and poison. KL-175 and KL-125 are used in the experiment by depending on the length of vaporizer fin. The experimental variable are composed of the length of vaporizer fin(2000 mm, 1800mm, 1600mm), and the mass flow rate by the length(6.7 m3/h, 7.1 m3/h, 7.5 m3/h). The temperature of the inlet and outlet of vaporizer is measured as well as the surface of vaporizer(fin and Tube). Based on the temperature data from the experiment, the heat transfer coefficient for calculating a vaporizing efficiency, and the correlation equation between Nusselt number and Rayleigh number are suggested.
Further, the numerical analysis was conducted in order to increase reliability of the experiment and add the data. The CFD program uses the ANSYS Fluent. The vaporizer, KL-175 and KL-125, is modeled in a simple structure. the accuracy of data is increased by giving Mesh minutely on the surface of the vaporized through the repetition interpretation. It is guaranteed the steady state of incompressibility so as to interpret the external fluid flow of ambient air vaporizer, and the temperature condition of the surface of vaporizer by the experiment would be a boundary condition. The temperature condition shows the experimental data by the changes of the length of vaporizer(2000 mm, 1800mm, 1600mm) and the mass flow rate by the length(6.7 m3/h, 7.1 m3/h, 7.5 m3/h). Moreover, with the changes of temperature by the length is supposed, the analysis on numerical value is conducted. The data from the numerical analysis and the experiment give the correlation equation regarding the ambient air vaporizer.
In this study, we can obtain the heat transfer coefficient that is essential to the vaporization efficiency, and accumulate the data for a design of heat exchanger.