Experimental Study on Application of Heat Transfer Enhancement Method Using Porous Material With High Porosity

A technology development of a hydrogen production system by nuclear heat is being performed as a heat application system of the Very High Temperature Reactor (VHTR) in worldwide. As for the development of the coupling technology between the VHTR and the hydrogen production system, Japan Atomic Energy Agency had carried out a coupling technology test using a steam reforming process by natural gas. In the hydrogen production system by nuclear heat, the catalyst tube of the steam reformer is heated by the high temperature helium gas from the intermediate heat exchanger (IHX). There are several methods for heat transfer enhancement. For example, there are attaching various fins on the heat transfer surface, processing the surface roughly, and so on. Disk type fins are attached on the outside surface of the catalyst tube. The catalyst tube is inserted into the guide tube to increase an amount of heat transferred from the high temperature helium gas. However, it has to take into consideration the deterioration of the structure strength by attaching the fins on the tube surface with the design of the steam reformer. The objective of this study is to clarify performances of a method for heat transfer enhancement using porous material with high porosity by an experiment. The experiment has been performed using an apparatus which simulated the passage structure of the steam reformer to obtain characteristics of heat transfer.