Study On Technologies Of Artificial Simulation Of Multiple Environment Parameters

This project aims to reproduce the environment mode of desert zones in a laboratory and modulate the environment parameters in a controllable way in order to study environment problems of desert zones systematically. The technologies are studied carefully for such environmental parameters as temperature, solar radiation and gust spectrum.According to characters of the simulated objects and on bases of re-development of ZUTAIKING software, a technology of the PID and PLC control is adopted to make the temperature environment simulated by computer. The results of the experiment simulations show that the technological factors can satisfy the design requirement (from -10°C to 50 ℃). Not only the control mode of constant temperature operating can be realized with the facility, but also a control mode that is based on a required daily temperature curve can be accomplished with a specified precision (less than or equal to ± 0.5℃).The differences in the radiation simulation criterions both at home and abroad are discussed according to the content and the requirement of different study objectives. The selection and design of the light source of whole spectrum solar simulator is finished in the environment simulation lab. The whole spectrum solar simulator is constituted by adopting a new type of dysprosium lamp for the first time in China. In order to find a convenient and economical light, based on the national standard "A general standard for the solar simulator" and the standard recommended by the American Society of Testing Materials (ASME), the investigation was conducted about the spectrum of no-film, single- film and multi-film halogen-tungsten lights and a new type of dysprosium light. It has been showed that the halogen-tungsten lights are not suitable for the solar simulator since their infrared energy accounts for a much greater portion in the total radiation and their technical performance is below the C level of the national standard. In contrast withthat, the dysprosium light is an excellent light for the full spectrum solar simulator. The index of its relative spectrum energy disorder error can reach the A level of the national standard in the wave length range of 250nm~400nm and 700nm~1000nm while the index reaches the B level of the national standard in the broader spectrum range of 250nm~2500nm.A 4500mm× 3880mm solar simulator has been constructed with the dysprosium lights placed in a configuration of plum blossom, which gives a radiation intensity of 1000w/m~2 in an effective radiation surface of 2000mm × 1500mm in area and 2m above the ground. The ununiformity of radiation and unsteadiness of the solar simulator have reached the B level of the national standard "A general standard for the solar simulator".A five order AR model has been established for the gust simulation based on the Yule—Walke method, and a corresponding program developed with Matlab. A good coherence was achieved between the simulative wind velocity signals and the original spectrum in the range of 0.02~lHz. A wind tunnel experiment was conducted with the simulative time serial of wind velocity of the Simiu spectrum. It was showed that there is a significant correlation between the original signals and experimental wind velocity signals with a correlation factor of greater than 0.85. The correlation factor is above 0.6 in the range less than 0.1 Hz.An on-site gust gradient survey has been conducted at the south edge of the Taklamakan desert for the first time in China, which has provided the benchmark data for further simulation investigations of the gust in the desert environment laboratory.Based on the above-mentioned studies an integrated environment simulation laboratory has been set up in the Xi'an Jiaotong University for researches on the desert environment. Experiment investigations can be conducted in the laboratory on the environmental conditions of high and low temperatures, solar radiation, gust as well as the surface and underground conditions of the desert geography.