Thermal Characters Of Regenerator And Optimal Design Research

High Temperature Air Combustion (HTAC) technology is a new combustion technology developed from the early 90s last century. High Temperature Air Combustion integrates recycling flue gas heat, high combustion efficiency and low NO_x emission into a new technology, and there are some advantages in HTAC, such as energy conversation, low NO_x emission and decreasing the scale of furnace. Now it has made a rapid progress in the latest years.The process and status of HTAC are reviewed in this thesis, its principles and characteristics are expatiated. The previous studies on HTAC home and abroad are introduced. And then the preparation and material selection of the regenerator are summarized; our lab's patent that preparation of new kind of high performance composite regenerator is presented at the same time and compared with normal material. In the experiment the thermal characteristics are tested, and the influencing laws of parameters in regenerative heat exchanger are validated. A program is founded to simulate the relations between thermal characteristics and operational parameters, structure parameters. It is found that all the two regenerative heat exchangers have the same operational laws, but the composite regenerator excel the normal regenerator. The effect of important parameters in the performance of a" regenerative heat exchanger is discussed as follow:1. With the extension of reversing time, the average exit temperature of preheated air decreases and that of flue gas rises, and the thermal efficiency and the temperature efficiency decrease, too.2. With the increase of flux (velocity), the average exit temperature of preheated air decreases and that of flue gas rises, and the thermal efficiency and the temperature efficiency decrease, too.3. Increasing the height of regenerative heat exchanger will raise average exit temperature of preheated air, temperature efficiency and thermal efficiency. On the contrary, the average exit temperature of flue gas will decrease.4. In a steady porosity, the bigger the specific surface area of regenerator is, the higher the average exit temperature of preheated air, the thermal efficiency and the temperature efficiency are, and the lower the average exit temperature of flue gas is. Otherwise if the porosity changes with the specific surface area, the above conclusion couldn't be assured.5. To increase specific heat will raise the thermal efficiency the temperature efficiency, and the average exit temperature of preheated air, and reduce the average exit temperature of flue gas.6. In design, the head loss is a parameter which should be paid more attention to. It's value can be influenced by operational parameters and structure parameters.At last, based on current design method, a program to design regenerative heat exchanger is exploited. It is proved that the software can be used in engineering design.The above conclusions give a reference to engineering design.