蒸氣噴射準(zhǔn)雙級(jí)壓縮制冷系統(tǒng)的實(shí)驗(yàn)研究
發(fā)布時(shí)間：2019-01-22 18:08
【摘要】：在蒸氣壓縮式制冷循環(huán)中,確定制冷工質(zhì)后,系統(tǒng)的蒸發(fā)壓力和冷凝壓力分別由蒸發(fā)溫度和冷凝溫度決定。蒸發(fā)溫度由系統(tǒng)的功能所決定,而冷凝溫度受環(huán)境介質(zhì)限制。當(dāng)蒸發(fā)溫度降低時(shí),壓縮機(jī)的壓縮比增大,由于壓縮機(jī)存在余隙容積,根據(jù)相關(guān)理論求解公式可以看出,隨著壓縮比的增大,壓縮機(jī)的余隙容積逐漸減小,當(dāng)壓縮比增加到某一數(shù)值后使得余隙容積降為零,此時(shí),壓縮機(jī)便不再吸氣,制冷量也隨之降為零。而本文利用噴射器提高引射流體的壓力而不直接消耗機(jī)械能的特點(diǎn),將其引入到單級(jí)蒸氣壓縮式制冷系統(tǒng)中,搭建蒸氣噴射準(zhǔn)雙級(jí)制冷系統(tǒng)實(shí)驗(yàn)臺(tái),并研究系統(tǒng)性能。噴射器利用壓縮機(jī)的排氣作為動(dòng)力,引射蒸發(fā)器出口的制冷工質(zhì),提高其壓力后送入壓縮機(jī)吸氣口,不僅降低了壓縮比,使系統(tǒng)獲得更低的蒸發(fā)溫度,而且沒有其余的機(jī)械能消耗。噴射器是蒸氣噴射準(zhǔn)雙級(jí)壓縮制冷系統(tǒng)的重要部件,本文用動(dòng)力函數(shù)法計(jì)算得到噴射器的基本尺寸,并在實(shí)驗(yàn)中探究其進(jìn)出口狀態(tài)參數(shù)變化對(duì)噴射系數(shù)以及系統(tǒng)性能的影響。此外,文中對(duì)壓縮機(jī)、蒸發(fā)器、冷凝器、膨脹閥及氣體噴射器建立數(shù)學(xué)模型,利用MATLAB語言編制相關(guān)計(jì)算程序,理論模擬系統(tǒng)性能。搭建實(shí)驗(yàn)臺(tái),此實(shí)驗(yàn)臺(tái)可以通過閥門的開關(guān)實(shí)現(xiàn)單級(jí)蒸氣壓縮式制冷循環(huán)與蒸氣噴射準(zhǔn)雙級(jí)壓縮制冷循環(huán)的兩種運(yùn)行方式,并在不同工況下對(duì)系統(tǒng)制冷量及系統(tǒng)性能的變化進(jìn)行實(shí)驗(yàn)研究。本文通過對(duì)蒸氣噴射準(zhǔn)雙級(jí)制冷系統(tǒng)和傳統(tǒng)單級(jí)蒸氣壓縮制冷系統(tǒng)的實(shí)驗(yàn)對(duì)比得出:蒸氣噴射準(zhǔn)雙級(jí)制冷系統(tǒng)可以獲得比單級(jí)蒸氣壓縮制冷系統(tǒng)更低的蒸發(fā)溫度,并且在較低的蒸發(fā)溫度下,蒸氣噴射準(zhǔn)雙級(jí)制冷系統(tǒng)性能優(yōu)于單級(jí)蒸氣壓縮制冷系統(tǒng);實(shí)驗(yàn)數(shù)據(jù)顯示,當(dāng)蒸發(fā)溫度降低到-22.57℃時(shí)(Tk=303.15K),蒸氣噴射準(zhǔn)雙級(jí)制冷系統(tǒng)的COP開始優(yōu)于單級(jí)蒸氣壓縮制冷系統(tǒng);當(dāng)蒸發(fā)溫度到-31.43℃時(shí)(Tk=308.15K),單級(jí)蒸氣壓縮式制冷系統(tǒng)將不再產(chǎn)生冷量,這是由于隨著壓比的不斷增大,壓縮機(jī)容積系數(shù)變?yōu)榱?壓縮機(jī)吸氣量隨之變?yōu)榱?雖然制冷系統(tǒng)仍在不斷運(yùn)行,但其制冷量卻為零,而本課題中測(cè)得蒸氣噴射準(zhǔn)雙級(jí)制冷系統(tǒng)可達(dá)到的最低蒸發(fā)溫度為-36.52℃。對(duì)氣體噴射器進(jìn)行實(shí)驗(yàn)研究,探究其進(jìn)出口參數(shù)的變化對(duì)噴射器噴射系數(shù)及系統(tǒng)性能、制冷量的影響。首先分析了噴射器出口流體壓力變化對(duì)噴射系數(shù)和系統(tǒng)性能及制冷量的影響。實(shí)驗(yàn)數(shù)據(jù)顯示:隨著混合流體出口壓力的增加,噴射系數(shù)逐漸降低,系統(tǒng)制冷量也呈下降趨勢(shì),但系統(tǒng)COP隨著混合出口流體壓力的變化曲線為二次曲線,當(dāng)噴射器進(jìn)口流體壓力為880KPa時(shí),混合流體出口壓力在220KPa~240KPa時(shí)系統(tǒng)COP較好;其次分析了工作流體對(duì)噴射系數(shù)及系統(tǒng)的影響。實(shí)驗(yàn)數(shù)據(jù)顯示:當(dāng)工作流體的壓力逐漸增加時(shí),噴射系數(shù)及系統(tǒng)COP、制冷量均呈現(xiàn)先增加后降低的趨勢(shì),在本文實(shí)驗(yàn)條件下,當(dāng)工作流體的壓力為900KPa~930KPa時(shí),系統(tǒng)COP較好;另外對(duì)噴射器引射流體的壓力與噴射系數(shù)及系統(tǒng)COP、制冷量間的關(guān)系進(jìn)行分析。分析實(shí)驗(yàn)數(shù)據(jù)可得:當(dāng)引射流體的壓力增加時(shí),噴射系數(shù)呈上升趨勢(shì),隨著噴射系數(shù)的逐漸增加,蒸氣噴射準(zhǔn)雙級(jí)制冷系制冷量呈現(xiàn)相同的變化趨勢(shì),但引射流體壓力與系統(tǒng)COP的變化曲線為二次曲線,當(dāng)引射流體的壓力為130KPa~150KPa時(shí),系統(tǒng)COP較好。
[Abstract]:In the vapor compression refrigeration cycle, the evaporation pressure and the condensation pressure of the system are determined by the evaporation temperature and the condensation temperature after the refrigeration working medium is determined. The evaporation temperature is determined by the function of the system, and the condensation temperature is limited by the ambient medium. when the evaporation temperature is reduced, the compression ratio of the compressor is increased, At this time, the compressor no longer inhales, and the cooling capacity also drops to zero. In this paper, the injector is used to improve the pressure of the injection fluid without directly consuming the mechanical energy. It is introduced into a single-stage vapor compression refrigeration system, and the experimental table of the vapor-injection quasi-dual-stage refrigeration system is set up, and the performance of the system is also studied. the ejector uses the exhaust of the compressor as the power to draw the refrigerant working medium at the outlet of the evaporator, and the pressure is increased to the suction port of the compressor, so that the compression ratio is reduced, the system can obtain lower evaporation temperature, and the rest of the mechanical energy is not consumed. The ejector is an important part of the vapor injection quasi-double-stage compression refrigeration system. The basic dimensions of the ejector are calculated by the power function method, and the effect of the change of the inlet and outlet state parameters on the injection coefficient and the system performance is investigated in the experiment. In addition, a mathematical model is established for compressor, evaporator, condenser, expansion valve and gas ejector, and the relevant calculation program and theoretical simulation system performance are prepared by using MATLAB language. The experiment table can be set up. The experiment table can realize the two modes of the single-stage vapor compression refrigeration cycle and the vapor injection quasi-double stage compression refrigeration cycle through the switch of the valve, and carry out the experimental research on the system cooling capacity and the system performance under different working conditions. by comparing the experimental results of a vapor-jet quasi-dual-stage refrigeration system and a conventional single-stage vapor compression refrigeration system, the vapor-jet quasi-dual-stage refrigeration system can achieve a lower evaporation temperature than a single-stage vapor compression refrigeration system and, at a lower evaporation temperature, The performance of the vapor-jet quasi-dual-stage refrigeration system is better than that of a single-stage vapor compression refrigeration system, and the experimental data show that the COP of the vapor-injection quasi-dual-stage refrigeration system is better than the single-stage vapor compression refrigeration system when the evaporation temperature is reduced to-22.57 DEG C (Tk = 303.15K). when the evaporation temperature is at-31.43. degree. C. (Tk = 308. 15K), the single-stage vapor compression refrigeration system will no longer generate a cold amount, because the compressor volume coefficient becomes zero as the pressure ratio increases, and the compressor suction amount becomes zero, although the refrigeration system is still running continuously, but the refrigerating capacity is zero, and the minimum evaporation temperature of the vapor injection quasi-double-stage refrigeration system measured in the subject is-36.52 DEG C. The effect of the change of the inlet and outlet parameters on the injection coefficient and the system performance and the cooling capacity of the ejector was investigated. The effect of the change of the fluid pressure on the injection coefficient and the system performance and the cooling capacity is analyzed. The experimental data show that, with the increase of the outlet pressure of the mixed fluid, the injection coefficient is gradually reduced, and the cooling capacity of the system is also decreasing, but the system COP is a quadratic curve with the change curve of the fluid pressure of the mixed outlet, and when the inlet fluid pressure of the ejector is 880KPa, The system COP is better when the outlet pressure of the mixed fluid is 220KPa-240KPa, and the effect of the working fluid on the injection coefficient and the system is also analyzed. The experimental data show that, when the pressure of working fluid is gradually increased, the injection coefficient and system COP and refrigerating capacity show a tendency to decrease, and under the experimental conditions of this paper, the system COP is better when the pressure of working fluid is 900KPa-930KPa. In addition, the relationship between the pressure and the injection coefficient and the system COP and the cooling capacity of the ejector fluid is analyzed. The experimental data can be obtained: when the pressure of the injection fluid is increased, the injection coefficient is on the rise, and with the gradual increase of the injection coefficient, the cooling capacity of the vapor injection quasi-dual-stage refrigeration system exhibits the same variation trend, but the change curve of the injection fluid pressure and the system COP is a quadratic curve, When the pressure of the injection fluid is 130KPa-150KPa, the system COP is better.
【學(xué)位授予單位】：天津商業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB657
本文編號(hào)：2413437
[Abstract]:In the vapor compression refrigeration cycle, the evaporation pressure and the condensation pressure of the system are determined by the evaporation temperature and the condensation temperature after the refrigeration working medium is determined. The evaporation temperature is determined by the function of the system, and the condensation temperature is limited by the ambient medium. when the evaporation temperature is reduced, the compression ratio of the compressor is increased, At this time, the compressor no longer inhales, and the cooling capacity also drops to zero. In this paper, the injector is used to improve the pressure of the injection fluid without directly consuming the mechanical energy. It is introduced into a single-stage vapor compression refrigeration system, and the experimental table of the vapor-injection quasi-dual-stage refrigeration system is set up, and the performance of the system is also studied. the ejector uses the exhaust of the compressor as the power to draw the refrigerant working medium at the outlet of the evaporator, and the pressure is increased to the suction port of the compressor, so that the compression ratio is reduced, the system can obtain lower evaporation temperature, and the rest of the mechanical energy is not consumed. The ejector is an important part of the vapor injection quasi-double-stage compression refrigeration system. The basic dimensions of the ejector are calculated by the power function method, and the effect of the change of the inlet and outlet state parameters on the injection coefficient and the system performance is investigated in the experiment. In addition, a mathematical model is established for compressor, evaporator, condenser, expansion valve and gas ejector, and the relevant calculation program and theoretical simulation system performance are prepared by using MATLAB language. The experiment table can be set up. The experiment table can realize the two modes of the single-stage vapor compression refrigeration cycle and the vapor injection quasi-double stage compression refrigeration cycle through the switch of the valve, and carry out the experimental research on the system cooling capacity and the system performance under different working conditions. by comparing the experimental results of a vapor-jet quasi-dual-stage refrigeration system and a conventional single-stage vapor compression refrigeration system, the vapor-jet quasi-dual-stage refrigeration system can achieve a lower evaporation temperature than a single-stage vapor compression refrigeration system and, at a lower evaporation temperature, The performance of the vapor-jet quasi-dual-stage refrigeration system is better than that of a single-stage vapor compression refrigeration system, and the experimental data show that the COP of the vapor-injection quasi-dual-stage refrigeration system is better than the single-stage vapor compression refrigeration system when the evaporation temperature is reduced to-22.57 DEG C (Tk = 303.15K). when the evaporation temperature is at-31.43. degree. C. (Tk = 308. 15K), the single-stage vapor compression refrigeration system will no longer generate a cold amount, because the compressor volume coefficient becomes zero as the pressure ratio increases, and the compressor suction amount becomes zero, although the refrigeration system is still running continuously, but the refrigerating capacity is zero, and the minimum evaporation temperature of the vapor injection quasi-double-stage refrigeration system measured in the subject is-36.52 DEG C. The effect of the change of the inlet and outlet parameters on the injection coefficient and the system performance and the cooling capacity of the ejector was investigated. The effect of the change of the fluid pressure on the injection coefficient and the system performance and the cooling capacity is analyzed. The experimental data show that, with the increase of the outlet pressure of the mixed fluid, the injection coefficient is gradually reduced, and the cooling capacity of the system is also decreasing, but the system COP is a quadratic curve with the change curve of the fluid pressure of the mixed outlet, and when the inlet fluid pressure of the ejector is 880KPa, The system COP is better when the outlet pressure of the mixed fluid is 220KPa-240KPa, and the effect of the working fluid on the injection coefficient and the system is also analyzed. The experimental data show that, when the pressure of working fluid is gradually increased, the injection coefficient and system COP and refrigerating capacity show a tendency to decrease, and under the experimental conditions of this paper, the system COP is better when the pressure of working fluid is 900KPa-930KPa. In addition, the relationship between the pressure and the injection coefficient and the system COP and the cooling capacity of the ejector fluid is analyzed. The experimental data can be obtained: when the pressure of the injection fluid is increased, the injection coefficient is on the rise, and with the gradual increase of the injection coefficient, the cooling capacity of the vapor injection quasi-dual-stage refrigeration system exhibits the same variation trend, but the change curve of the injection fluid pressure and the system COP is a quadratic curve, When the pressure of the injection fluid is 130KPa-150KPa, the system COP is better.
【學(xué)位授予單位】：天津商業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB657
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