發(fā)布時(shí)間：2018-04-19 10:18

  本文選題：噴射器 + 冷藏車��； 參考：《山東大學(xué)》2017年碩士論文

【摘要】：隨著經(jīng)濟(jì)的快速發(fā)展,人們的生活水平有了顯著提高,因此對(duì)食品的品質(zhì)和多樣性提出了更高的要求,與之密切相關(guān)的冷鏈物流業(yè)也進(jìn)入了高速發(fā)展期。但作為運(yùn)輸載體的冷藏車,尤其是其制冷系統(tǒng)能耗大,燃料利用率低,加劇了能源緊張問(wèn)題。由于結(jié)構(gòu)簡(jiǎn)單、成本低、能耗小等特點(diǎn),噴射式制冷系統(tǒng)在眾多制冷方法中獨(dú)具優(yōu)勢(shì),但是有限的升壓能力成為制約噴射式制冷系統(tǒng)應(yīng)用到冷藏車的瓶頸。本文提出了一種較大升壓能力的兩級(jí)噴射器,為將噴射式制冷系統(tǒng)應(yīng)用到冷藏車上進(jìn)行了有益探索。該研究對(duì)冷藏車的節(jié)能減排有重要的理論及應(yīng)用價(jià)值。首先,在設(shè)計(jì)工況下提出了一種兩級(jí)噴射器的設(shè)計(jì)方法。選擇帶有實(shí)驗(yàn)數(shù)據(jù),國(guó)際公認(rèn)的噴射器模型作為原型,通過(guò)數(shù)值模擬的方式對(duì)原型噴射器進(jìn)行了建模和基于實(shí)驗(yàn)數(shù)據(jù)的校正,找到了快速高效的數(shù)值模擬方法。在原型噴射器的基礎(chǔ)上,依據(jù)工況,通過(guò)改變影響噴射器性能的喉嘴比和NXP等關(guān)鍵結(jié)構(gòu)尺寸,分別設(shè)計(jì)了第一級(jí)和第二級(jí)噴射器。同時(shí)依據(jù)第一級(jí)和第二級(jí)噴射器串聯(lián)的原則,將第一、二級(jí)噴射器整合成兩級(jí)噴射器,并建立了該兩級(jí)噴射器的三維模型。其次,以R134a作為制冷劑,在工作流體溫度為63～74℃,蒸發(fā)溫度為-24～0℃范圍內(nèi),對(duì)建立的兩級(jí)噴射器模型進(jìn)行了性能分析。研究了兩級(jí)噴射器內(nèi)部的速度場(chǎng)、壓力場(chǎng)、溫度場(chǎng)等分布,同時(shí)對(duì)兩級(jí)噴射器內(nèi)部的激波位置進(jìn)行了捕捉。還研究了工作流體、引射流體及出口工況變化時(shí),兩級(jí)噴射器的性能變化,找到了兩級(jí)噴射器工作條件變化對(duì)其性能的影響規(guī)律。研究發(fā)現(xiàn):1)當(dāng)兩級(jí)噴射器的二次流壓力恒定時(shí),臨界背壓隨著一次流壓力的增加而增加,而兩級(jí)噴射器的最大噴射系數(shù)卻隨著一次流壓力的增加而逐漸減小;2)當(dāng)一次流壓力變大時(shí),兩級(jí)噴射器的臨界背壓和最大噴射系數(shù)都隨著二次流壓力的增加而變大;3)當(dāng)兩級(jí)噴射器的引射流體壓力和背壓都恒定時(shí),兩級(jí)噴射器的噴射系數(shù)伴隨工作流體壓力的增加先增大后減小,存在一個(gè)最大噴射系數(shù),同時(shí)在飽和狀態(tài)下,蒸發(fā)溫度分別為-22℃、-20℃、-18℃時(shí),相應(yīng)的最大噴射系數(shù)分別為0.0736、0.0761、0.0813。最后,對(duì)冷藏車廂體不同溫區(qū)下冷藏車總耗冷量進(jìn)行了分析。通過(guò)計(jì)算得到冷藏車廂體溫度分別為0℃、-5℃、-14℃和-18℃時(shí)冷藏車的總耗冷量分別為7.69kw、9.21kw、11.94kw、13.53kw。而冷藏車排量都比較大,其廢熱量一般在20kw以上,因此冷藏車的廢熱量能夠滿足噴射式制冷需要。綜上,通過(guò)對(duì)設(shè)計(jì)的兩級(jí)噴射器的研究,表明將噴射制冷技術(shù)應(yīng)用到冷藏車上實(shí)現(xiàn)節(jié)能減排的方法是可行的,本研究作為廢熱驅(qū)動(dòng)噴射式制冷系統(tǒng)在冷藏車上的應(yīng)用具有重要的指導(dǎo)意義。
[Abstract]:With the rapid development of economy, people's living standard has been improved significantly, so the quality and diversity of food are required higher, and the cold-chain logistics industry, which is closely related to it, has also entered a period of rapid development.However, refrigerated vehicle as a carrier, especially its refrigeration system has a large energy consumption and low fuel utilization ratio, which exacerbates the problem of energy shortage.Because of its simple structure, low cost and low energy consumption, the ejector refrigeration system has unique advantages in many refrigeration methods, but the limited boost capacity has become a bottleneck for the application of jet refrigeration system to refrigerated vehicles.In this paper, a two-stage ejector with high boost capacity is proposed, which is useful for the application of ejector refrigeration system to refrigerated vehicles.This study has important theoretical and practical value for energy saving and emission reduction of refrigerated vehicles.Firstly, a design method of two-stage ejector is proposed under the design condition.The internationally recognized ejector model with experimental data was selected as the prototype. The prototype ejector was modeled and calibrated based on experimental data by numerical simulation, and a fast and efficient numerical simulation method was found.Based on the prototype ejector, the first stage and the second stage of the ejector are designed by changing the throat nozzle ratio and the key structure size of NXP, which affect the performance of the ejector.At the same time, according to the principle of the first and second stage ejector in series, the first and second stage ejector is integrated into two stage ejector, and the three-dimensional model of the two stage ejector is established.Secondly, using R134a as refrigerant, the performance of the two-stage ejector model is analyzed in the range of working fluid temperature of 6374 鈩，

本文編號(hào)：1772682