本文選題：空氣制冷 + 透平膨脹機��； 參考：《天津商業(yè)大學》2014年碩士論文

【摘要】：空氣循環(huán)制冷系統(tǒng)的制冷劑是空氣，作為天然制冷劑，對環(huán)境無任何污染，是未來可選擇的替代制冷劑；但空氣循環(huán)制冷系統(tǒng)性能系數(shù)偏低，因此對于空氣制冷系統(tǒng)而言，改善其制冷性能意義重大。更重要的是，由于空氣中的水蒸氣在渦輪中冷凝成水或結(jié)冰，這對系統(tǒng)的運行危害極大。不僅要提高空氣制冷系統(tǒng)的效率，同時也要降低系統(tǒng)中空氣含濕量，對這兩方面進行研究具有重要的理論及實際意義。 為了有效降低渦輪進口壓縮空氣的含濕量，本文在原有空氣循環(huán)制冷系統(tǒng)中增加了高效氣水分離器，除去渦輪進口濕空氣中攜帶的冷凝游離水，并對低溫箱進行改進，以提高系統(tǒng)運行的性能。試驗臺改進后，在不同的工況條件下，對三種回熱循環(huán)流程的空氣制冷系統(tǒng)的性能進行數(shù)值模擬和實驗研究，最后分析結(jié)果，得出如下結(jié)論： (1)模擬和實驗結(jié)果表明，對系統(tǒng)的制冷效率而言，壓氣機進口壓力的升高，增大了渦輪的膨脹比，降低了渦輪的出口溫度，提高了系統(tǒng)COP和制冷量。模擬結(jié)果顯示，在二級回熱流程下，，當壓氣機進口壓力由170kPa升高到200kPa時，系統(tǒng)COP升高了約33%。在相同條件下實驗值的增幅稍小，約升高了30%。對系統(tǒng)的除水性能而言，模擬和實驗結(jié)果表明，壓氣機進口壓力的升高對渦輪進口空氣的含濕量幾乎沒有影響，但渦輪中水蒸氣的冷凝量隨著壓氣機進口壓力的升高顯著增加，實驗中無回熱方案下增加最明顯。 (2)模擬和實驗結(jié)果表明，在系統(tǒng)中增設(shè)回熱器及相應(yīng)的水分離器，可顯著提高系統(tǒng)制冷效率和除水性能。模擬結(jié)果表明，與無回熱相比，二級回熱系統(tǒng)中的渦輪進口含濕量最多可下降44%，而相同條件下實驗值稍小，約為40%。同時，回熱器的增加也提高了系統(tǒng)制冷量，改善了系統(tǒng)COP。實驗結(jié)果表明，在壓氣機進口壓力為200kPa時，二級回熱系統(tǒng)的COP較無回熱系統(tǒng)提高了約40%，相同條件下模擬結(jié)果COP的增幅約為48%。 (3)模擬和實驗結(jié)果表明，系統(tǒng)COP和系統(tǒng)制冷量均隨制冷溫度的升高而增加。實驗結(jié)果表明，對二級回熱流程，當壓氣機進口壓力為200KPa時，制冷溫度從-20℃升高到-10℃時，系統(tǒng)的COP從0.23升高到0.38，升高了約65%，而相同條件下的仿真結(jié)果系統(tǒng)COP僅升高了36%。對于除水性能而言，模擬結(jié)果表明，渦輪進口空氣含濕量和渦輪中水蒸氣的冷凝量都隨制冷溫度的升高而增加。在壓氣機進口壓力為200kPa時，當系統(tǒng)制冷溫由-25℃升高到-5℃時，渦輪進口空氣含濕量由0.927g/kg增至1.24g/kg，增加了約34%。 (4)實驗結(jié)果表明，隨壓氣機壓比的升高，渦輪膨脹比不斷增大且增大速率變快。渦輪的折合流量隨渦輪膨脹比的增加而增大，且當渦輪膨脹比約為3時，折合流量達到最大值。
[Abstract]:The refrigerant of the air cycle refrigeration system is air. As a natural refrigerant, it is not polluting the environment and is the alternative refrigerant in the future. However, the performance coefficient of the air cycle refrigeration system is low, so for the air refrigeration system, It is of great significance to improve its refrigeration performance. More importantly, because the vapor in the air condenses into water or freezes in the turbine, it does great harm to the operation of the system. Not only to improve the efficiency of air refrigeration system, but also to reduce the moisture content of air in the system, it is of great theoretical and practical significance to study these two aspects. In order to effectively reduce the moisture content of the compressed air at the inlet of the turbine, an efficient air-water separator is added to the original air cycle refrigeration system to remove the condensed free water carried in the wet air at the inlet of the turbine, and the cryogenic box is improved. To improve the performance of the system. After the improvement of the test rig, the performance of the air refrigeration system of three regenerative cycle processes is simulated and experimentally studied under different operating conditions. Finally, the results are analyzed and the following conclusions are obtained: 1) the simulation and experimental results show that the increase of compressor inlet pressure increases the expansion ratio of the turbine, decreases the outlet temperature of the turbine, and increases the system COP and refrigerating capacity for the refrigeration efficiency of the system. The simulation results show that when the inlet pressure of the compressor increases from 170kPa to 200kPa, the COP of the system increases about 33% under the two-stage regenerative process. Under the same conditions, the experimental value increased slightly, about 30%. The simulation and experimental results show that the inlet pressure of the compressor has little effect on the moisture content of the inlet air, but the condensing capacity of the steam in the turbine increases significantly with the increase of the inlet pressure of the compressor. In the experiment, the increase is most obvious under the scheme of no regenerative heat. 2) the simulation and experimental results show that the cooling efficiency and water removal performance of the system can be significantly improved by adding a regenerator and a corresponding water separator in the system. The simulation results show that the inlet moisture content of the turbine in the secondary regenerative system can be decreased by up to 44 and the experimental value under the same conditions is slightly smaller than that of the non-regenerative system, which is about 40 parts. At the same time, the increase of regenerator also increases the cooling capacity of the system and improves the system COP. The experimental results show that when the inlet pressure of the compressor is 200kPa, the COP of the secondary regenerative system is about 40% higher than that of the non-regenerative system, and the increase of COP is about 48% under the same conditions. The simulation and experimental results show that both the system COP and the cooling capacity increase with the increase of the refrigeration temperature. The experimental results show that when the inlet pressure of the compressor is 200KPa, the COP of the system increases from 0.23 to 0.38 when the inlet pressure of the compressor is increased from -20 鈩

本文編號：1842198