發(fā)布時間：2018-03-05 05:00

  本文選題：噴射式制冷　切入點：無泵　出處：《浙江大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：利用低品位熱能驅(qū)動的制冷系統(tǒng)可以有效減少化石能源的消耗,在傳統(tǒng)能源消耗巨大、環(huán)境問題越加顯著的今天,越來越受到人們的關(guān)注。噴射式制冷系統(tǒng)在有效利用太陽能熱和各種余熱等低品位熱能的同時,可以使用水等天然工質(zhì)進行制冷,是理想的環(huán)保型制冷系統(tǒng)之一。除此之外,噴射制冷系統(tǒng)還具有結(jié)構(gòu)簡單、初投資低、運行穩(wěn)定等優(yōu)點。為了提高噴射式制冷系統(tǒng)的性能,實現(xiàn)噴射式制冷系統(tǒng)完全由熱能驅(qū)動的目標(biāo),本文主要研究了無泵閥切換噴射式制冷系統(tǒng)的運行規(guī)律和工作特性,并在理論研究的基礎(chǔ)上進行了實驗驗證。研究內(nèi)容如下:1)介紹了噴射器的工作原理、噴射式制冷系統(tǒng)的研究現(xiàn)狀,以及影響噴射式制冷系統(tǒng)性能的主要因素。對已有無泵閥切換噴射式制冷系統(tǒng)進行了改進和完善,提升了系統(tǒng)的控制與測量精度,簡化了操作過程。2)采用一維等壓模型對噴射器進行了理論研究與工作參數(shù)模擬,得到了發(fā)生壓力、冷凝壓力和蒸發(fā)壓力對系統(tǒng)性能的影響。在分析儲液罐容積對系統(tǒng)穩(wěn)定性的影響的基礎(chǔ)上對儲液罐容積進行了優(yōu)化。3)通過對無泵閥切換噴射式制冷系統(tǒng)工作原理的分析,認為該系統(tǒng)的最佳循環(huán)過程應(yīng)該是儲液罐蓄滿水后再回水,回水必須完全。所以,系統(tǒng)蓄水時間和回水時間應(yīng)該根據(jù)具體工況和儲液罐容積來設(shè)定。在系統(tǒng)最佳狀態(tài)下,無泵閥切換噴射式制冷系統(tǒng)的性能隨發(fā)生壓力的升高先升高后下降,發(fā)生壓力為130 kPa左右時系統(tǒng)性能達到最佳;蒸發(fā)壓力越高系統(tǒng)性能越好;冷凝壓力小于臨界背壓時,冷凝壓力的變化對系統(tǒng)性能幾乎沒有影響,當(dāng)冷凝壓力大于臨界背壓時,隨冷凝壓力升高系統(tǒng)性能急劇下降。4)實驗結(jié)果和理論研究都揭示了無泵閥切換噴射式制冷系統(tǒng)在工作過程中發(fā)生壓力、冷凝壓力與蒸發(fā)壓力的變化對系統(tǒng)運行參數(shù)與性能的影響規(guī)律。理論研究與實驗結(jié)果具有良好的一致性,為深入探究無泵閥切換噴射式制冷系統(tǒng)的工作特性打下一定的基礎(chǔ)。
[Abstract]:The refrigeration system driven by low-grade heat energy can effectively reduce the consumption of fossil energy. More and more people pay more and more attention to it. The ejector refrigeration system is one of the ideal environmental protection refrigeration systems, which can use natural refrigerants such as water and other low-grade heat energy to make effective use of solar energy and all kinds of waste heat. The ejector refrigeration system also has the advantages of simple structure, low initial investment, stable operation and so on. In order to improve the performance of the ejector refrigeration system, it can realize the goal that the ejector refrigeration system is completely driven by heat energy. In this paper, the operating rules and working characteristics of the switched ejector refrigeration system without pump valves are studied, and the experimental verification is carried out on the basis of theoretical research. The work principle of the ejector is introduced as follows: 1. The present research situation of jet refrigeration system and the main factors affecting the performance of jet refrigeration system have been improved and perfected, and the control and measurement accuracy of the system has been improved. The operation process is simplified. 2) A one-dimensional isobaric model is used to study the ejector theoretically and simulate the working parameters, and the pressure is obtained. The effect of condensing pressure and evaporation pressure on the system performance. Based on the analysis of the effect of tank volume on system stability, the tank volume is optimized. 3) the working principle of the switched jet refrigeration system without pump valves is analyzed. It is considered that the optimal circulation process of the system should be that the tank is filled with water, and the backwater must be returned completely. Therefore, the storage time and backwater time of the system should be set according to the specific working conditions and the volume of the tank, and in the best condition of the system, The performance of the switched injection refrigeration system without pump valve increases first and then decreases with the increase of pressure. The system performance reaches the best when the occurrence pressure is about 130 kPa; the higher the evaporation pressure, the better the system performance; when the condensing pressure is less than the critical back pressure, The change of condensing pressure has little effect on the performance of the system. When the condensing pressure is greater than the critical back pressure, The experimental results and theoretical studies show that the pressure of the switched injection refrigeration system without pump valves occurs in the working process, and the performance of the system decreases sharply with the increase of condensing pressure. The effect of condensing pressure and evaporation pressure on the operating parameters and performance of the system is in good agreement with the experimental results, which lays a foundation for further exploring the working characteristics of the switched jet refrigeration system without pump valves.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TB657

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本文編號：1568812