Article ID: 23-30_OA
We propose a method to enhance boiling heat transfer on the inner surface of a pipe by grooving the inner surface and filling the grooves with silicone sealant. Experiments were conducted to measure temperature variation of a pipe cooled with liquid nitrogen and liquid hydrogen. Stainless steel pipes with an outside diameter of 1/2 inch (12.7 mm) and a length of 120 mm were used in the experiments. Experiments were conducted using the pipes having different spacing of the grooves on the inner surface. The effect on the cooling rate and the heat flux calculated from the temperature variation in time were investigated. In the experiments using liquid nitrogen, the modified pipe reduced the cooling time by 1/3.6 due to the suppression of film boiling. By contrast, the cooling time could not be reduced in the experiment using liquid hydrogen. The unique physical properties of hydrogen and its heat transfer characteristics may have affected the results.
