Measuring Of Gas-Liquid Temperture And Investigation Of Heat And Mass Transfer Of Gas-Liquid Flow In Saturator Of HAT Cycle

Humid air turbine (HAT) cycle is well known for high efficiency, high specific power, low NOx emissions etc. The saturator is a key unit in HAT cycle, and its heating and humidifying performance has important impact on the holistic performance of HAT cycle. There is a complex gas-liquid two-phase flow inside the saturator. In order to improving the performance of HAT cycle, the heat and mass transfer of gas-liquid flow in the saturator must be studied in detailed. Lots of previous research on the saturator including the theory and the experiment has been done and some valuable data has been obtained. But still very few studies are about the measurement of temperature in the gas-liquid two-phase flow, and the heat and mass transfer mechanism between gas and liquid should be further studied. Therefore, this work aims to solve these problems with experiment and mathematical simulation methods. Experiment is carried to measure the temperature of the gas-liquid two-phase flow inside the saturator. The complex gas-liquid flow is simplified abstractly, and numerical simulation method is used to study the impact of geometric parameters and aerodynamic parameters on heat and mass transfer.According to the size of the developed packing saturator, relative humidity measurement technology and gas-liquid separation technology, a special device is developed to be used to measure the relative humidity of humid air and the temperature of gas phase and liquid phase in the saturator. Under different inlet water temperature and liquid-gas ratio, the temperature of gas and liquid phase and the relative humidity of humid air along the height of the saturator were measured. According to the experimental data, a few conclusions can be obtained: the relative humidity and the moisture content of the outlet air increase as the liquid-gas ratio increased; temperature of inlet water have obvious influence on temperature of outlet air in high liquid-gas ratio conditions, and temperature of outlet air increases with the increase of temperature of inlet water.According to the characteristics of the gas-liquid two-phase flow in the high-pressure packing saturator, the complex gas-liquid flow inside the packed saturator can be simplified to gas-liquid two-phase falling film on a plate abstractly, using the assumption of the wall equivalent method. Base on the N-S equations, VOF analysis methods for two-phase flow and self-developed analysis software package including mass and energy source term, a computational model for the simulation of the heat and mass transfer in gas-liquid two-phase flow is established. The influence of fluctuation, inner liquid and gas velocity, inner liquid temperature and structure of the wall on the mass transfer in gas-liquid two-phase flow are analyzed with the computational model. The results indicated that the film fluctuation, higher inner water and air velocity, higher inner water temperature and the ripple of the wall can enhance the heat and mass transfer in gas-liquid two-phase flow.The heating and mass transfer of the complex gas-liquid two-phase flow in the saturator is studied in detail in this paper. The conclusions are very important for the high performance saturator development.