【作者】 李新中；

【导师】 王瑞祥；

【作者基本信息】 北京建筑工程学院 ， 供热、供燃气通风及空调工程， 2010， 硕士

【摘要】 通过将系统中的冷冻机油置换为纳米冷冻机油的方式,在制冷系统中应用纳米粉体材料是提高设备能效、延长设备寿命的重要方法。本文通过实验的方法考察纳米粒子在冷冻机油中的分散稳定性,在此基础上,开展添加纳米粒子的含油制冷剂饱和蒸气压的研究,以期为纳米粒子在含油制冷剂中的应用提供基础数据,同时对纳米粒子在含油制冷剂中的作用机理进行分析,探索纳米冷冻机油对制冷剂饱和蒸气压影响的规律。主要工作包括:1.纳米冷冻机油的制备及其分散稳定性研究通过超声震荡和添加合适的分散剂的方法,制备出纳米CuO冷冻机油和纳米NiFe2O4冷冻机油并采用沉降观测法和紫外-可见吸收光谱法考察了所制备的纳米冷冻机油的分散稳定性。研究发现:(1)通过添加合适的分散剂可以改善纳米粒子在矿物油中的分散稳定性,且对应一定含量的纳米粒子,分散剂有一个最佳的量,并非越多越好;(2)震荡加热时需选择低频率超声分散方式和合适的低温,才能达到较好的分散稳定效果;而利用加热箱直接加热时,高温条件下得到的纳米冷冻机油的分散稳定效果较好。2.纳米冷冻机油对制冷剂饱和蒸气压影响规律的实验研究采用稳态法,在263k～323k范围内,首先测量了纯制冷剂R134a和R22的饱和蒸气压,通过与NIST提供的标准数据相比较,最大偏差分别为-0.191和-0.183;标准偏差分别为0.095和0.103,验证了测试系统的精度。在263k～323k范围内,分别测量了纯制冷剂、含油制冷剂、含分散剂油溶胶的制冷剂和含纳米冷冻机油制冷剂的饱和蒸气压。测试结果表明:(1)含油制冷剂的饱和蒸气压小于纯制冷剂的饱和蒸气压,二者之间的差值随着冷冻机油含量的增加而增大;(2)在冷冻机油含量相同的条件下,矿物油对R22饱和蒸气压的影响大于POE油对R134a饱和蒸气压的影响;(3)在不含纳米粒子的条件下,矿物油对R134a的饱和蒸气压的影响小于POE冷冻机油相对R134a的饱和蒸气压的影响。其中:含量为5%时,矿物油:最大偏差为-0.627,标准偏差为0.376; POE油:最大偏差为-2.514,标准偏差为0.839;(4)在含油量相同的条件下,分散剂矿物油溶胶对R134a饱和蒸气压的影响与相应的纯矿物冷冻机油的影响相当。其中:含量为5%时,矿物油:最大偏差为-0.627,标准偏差为0.376; SDBS油溶胶:最大偏差为-0.365,标准偏差为0.216; Span80油溶胶:最大偏差为-0.827,标准偏差为0.530;(5)含有纳米冷冻机油的制冷剂的饱和蒸气压低于含油制冷剂或纯制冷剂的饱和蒸气压,差值随着纳米冷冻机油含量的增加而增大;(6)矿物纳米冷冻机油对R134a饱和蒸气压的影响与相应的纯POE冷冻机油的影响相当。其中:含量为5%时,纯POE油:最大偏差为-2.514,标准偏差为0.839;纳米CuO冷冻机油:最大偏差为-2.128,标准偏差为0.745;纳米NiFe2O4冷冻机油:最大偏差为-2.658,标准偏差为0.828。更多还原

【Abstract】 Application of nano-powder materials in refrigeration system, by way of replacing refrigeration oil with nano refrigeration oil, is an important means to improve the energy efficiency of a refrigerator as well as to extend the equipment life.In this paper, dispersion stability of nano-particles in nano refrigeration oil was studied by experiments. The saturated vapor pressure of refrigerant that mixed with mineral nano refrigeration oil was measured. The purpose of this paper is to provide base data for application of nano-particles in the refrigerant that mixed with mineral oil, and to analyze the mechanism of nano-particles in the refrigerant that mixed with mineral oil as well as to explore the rule that impaction of nano refrigeration oil on the saturated vapor pressure of refrigerant.The main works included:1. Preparation of nano refrigeration oil and its stability.Nano-CuO refrigeration oil and nano-NiFe2O4 refrigeration oil ware prepared by means of ultrasonic concussion and adding appropriate dispersant. By way of observation of settlement and UV-visible absorption spectroscopy, the dispersion stability of nano refrigeration oil was estimated.The results show that:(1) Adding appropriate dispersant could significantly improve the dispersion stability of nano-particles in mineral oil, and corresponds to a certain content of nano-particles, the amount of dispersant had an optimal value, not the more the better.(2) In order to achieve good dispersion stabilizing effect, that concussion heating should choose the low-frequency ultrasound and suitable low temperature, however when using the heating tank, high temperature is better.2. Impaction of nano-refrigeration oil on the saturated vapor pressure of refrigerant.By way of the steady-state method, the saturated vapor pressure of pure refrigerant R134a and R22 were measured at the range of 263k~323k. The test data were compared with the standard data provided by NIST to verify the reliability of test system and the accuracy of the test data. The maximum deviation were -0.191 and -0.183 respectively, standard deviation were 0.095 and 0.103 respectively.At the range of 263k~323k, the saturated vapor pressure of pure refrigerant and that of the mixtures of the refrigerant respectively mixed with mineral refrigeration oil, dispersion oil sol, and mineral nano refrigeration oil were measured.The results as fellows:(1) The saturated vapor pressure of refrigerant mixed with mineral refrigeration oil is lower than that of the pure refrigerant, and the difference between them is higher as the mass fraction of refrigeration oil increased;(2) Under the condition of the same mass fraction of refrigeration oil, impaction of mineral oil on the saturated vapor pressure of R22 is greater than that of POE oil on the saturated vapor pressure of R134a.(3) When there is no nano-particles, impaction of mineral oil on the saturated vapor pressure of R134a is less than that of POE on the saturated vapor pressure of R134a. Where, when the mass fraction is 5%, Mineral oil: maximum deviation is -0.627, standard deviation is 0.376; POE oil: maximum deviation is -2.514, standard deviation is 0.839;(4) When with the same mass fraction of refrigeration oil in the refrigerant, impaction of dispersion mineral oil sol on the saturated vapor pressure of R134a is equivalent that of the pure mineral refrigeration oil on the saturated vapor pressure of R134a. Where, when the mass fraction is 5%, Mineral oil: maximum deviation is -0.627, standard deviation is 0.376; SDBS oil sol: maximum deviation is -0.365, standard deviation is 0.216; Span80 oil sol: maximum deviation is -0.827, standard deviation is 0.530;(5) The saturated vapor pressure of refrigerant mixed with nano refrigeration oil is lower than that of refrigerant mixed with pure mineral oil or that of pure refrigerant, and the difference falls as the mass fraction of nano refrigeration oil drops;(6) Impaction of mineral nano refrigeration oil on the saturated vapor pressure of R134a is equivalent that of pure POE on the saturated vapor pressure of R134a. Where, when the mass fraction is 5%, Pure POE oil: maximum deviation is -2.514, standard deviation is 0.839; Nano-CuO refrigeration oil: maximum deviation is -2.128, standard deviation is 0.745; Nano-NiFe2O4 refrigeration oil: maximum deviation is -2.658, standard deviation is 0.828;更多还原