Critical heat flux (CHF) and flow boiling characteristics in parallel flow boiling channels simulating soot burning were experimentally investigated. This, for the purpose of prevention of a soot-fire on an exhaust gas economizer. Heat load by exhaust gas was simulated by uniformly heating parallel heated tubes through electrodes from two direct current power sources, respectively. Soot burning was simulated by non-uniformly heating only the other heated tube. Three gas burners were used or by increasing only the electric power. The inside diameter and length of the heated tubes were 4.35 and 1,000 mm, respectively. The main results are as follows: CHF in the soot burning tube first occurs near the heated tube exit. The point of sharp rise in tube wall temperature shifts on the upstream side with increasing time and / or heat flux. Flow rate in each heated tube, the pressure drop between pressure heads, or the total circulating flow rate monitoring system, is effective in order to early detect soot burning from the point of view of flow boiling characteristics.
