【作者】 孙青梅；

【导师】 米镇涛；

【作者基本信息】 天津大学 ， 化学工艺， 2006， 硕士

【摘要】 航空燃料的临界温度和临界压力数据是燃料性能评价的重要参数,直接影响着燃料在未来的航天飞机及高超音速飞行器中的使用状态及应用范围。对于研究燃料在超临界、近临界状态下的热裂解、热聚合、碳沉积现象及机理也有着其重要的理论价值。航空燃料一般成分复杂,不稳定,临界温度和临界压力值偏高,测量其临界性质难度较大。本文综述了测定物质临界性质的测定原理及方法,选用并改进了测定不稳定物质临界参数的低停留时间流动法,建立了完整的实验装置,拓展了测量范围,适合于不稳定体系和稳定体系临界温度和临界压力的测定,测试压力:0~5MPa,测试温度:0~500°C。以正戊烷、正己烷、环己烷及正十烷四种物质为标准试剂,对该装置进行了可靠性校核,其临界温度和临界压力偏差分别小于0.28°C和0.006MPa,该结果表明,所设计的装置进行不稳定物质的临界性质的测定是可靠的。本工作利用此装置首次测定了吸热型碳氢燃料RP-3、仿JP-7的临界温度和临界压力,同时测量了高密度燃料JP-10及与降闪剂甲基环己烷(MCH)混合物的临界参数。研究了二元混合物JP-10/MCH临界性质的变化规律。采用六种不同的估算方法对航空用吸热燃料RP-3和仿JP-7的临界参数进行了估算,结果表明,各计算方法所得临界温度值比较接近,最大偏差6.63°C,而临界压力计算值相差较大,最大偏差为0.828MPa,估算温度和压力的最大相对偏差分别为1.67%和38.4% ,为实验测量提供了一定的依据。与实验值相比较,API method和Riazi and Daubert Correlation两种方法较为可靠。本文提出了一种利用高压差示扫描量热仪(PDSC)估测物质临界温度和临界压力的新方法,通过测量不同压力下物质的DSC曲线,得到物质的临界点性质。并测定了正戊烷和JP-10的临界参数,分别为197.6°C、3.37MPa和423.8°C、3.60MPa,与文献值基本一致,完全能满足工业应用的精度要求。更多还原

【Abstract】 Critical temperatures and pressures of fuels are important parameters for rating of merit, which define the phase behaviors,performance and temperature range of fuels applied in the airplanes and hypersonic aircrafts. In addition, they are very useful in the investigation of the thermal degradation or aggregation, and carbon deposit under sub-supercritical conditions of fuels.It is generally difficult to measure the critical data of fuels due to its complex composition, unstable features and higher critical values.In this thesis, various experimental methods and theory to determine critical properties of substance were introduced. One low residence time flow equipment for the measurement of the critical temperatures and pressures of thermal-unstable fluids was designed. It improved the original methods and enlarged the range of temperatures and pressures measured, with the tested temperature as 0~500°C, and tested pressure as 0~5MPa. N-pentane、n-hexane、cyclohexane and n-decane were used as standard reagents to check the reliability of the apparatus. The maximum deviation of temperature and pressures are 0.28°C and 0.006MPa, respectively. These results fully prove that the apparatus is reliable to determine the critical data of thermal unstable fluids. The critical temperatures and pressures of two endothermic hydrocarbon fuels RP-3 and simulate JP-7, one high energy fuels JP-10 and mixtures of JP-10 with methyl cyclohexane (MCH) were determined for the firsttime.In addition, the critical data of endothermic aviation fuels of RP-3 and simulate JP-7 were estimated using 6 methods. The temperature deviation was less than 6.63°C, and the pressure deviations among estimated methods, however, can be as much as 0.828MPa. The maximum relative error of temperatures and pressures were 1.67%and 38.4%, respectively. The API methods, and Riazi and Daubert correlation are relatively reliable.A new method to determine the critical data using high pressure differential scanning calorimetry was proposed, which can inferred the critical temperatures and pressures from various DSC curves under differences measuring pressure. The critical data of n-pentane and JP-10 were obtained from this method, the results were 197.6°C and 3.37 MPa, 423.8°C and 3.60 MPa, respectively. The results were in good agreement with the published data, indicating that this method is reliable in practical更多还原