本文選題：R32 + 流動(dòng)沸騰��； 參考：《清華大學(xué)》2015年碩士論文

【摘要】：R32作為R22的替代工質(zhì)之一,具有環(huán)保、安全、流動(dòng)和傳熱性能優(yōu)異,易于獲得和工程使用等優(yōu)點(diǎn)。微細(xì)通道換熱效率高,被廣泛應(yīng)用于各個(gè)領(lǐng)域。R32在微細(xì)通道中的流動(dòng)沸騰流動(dòng)和傳熱特性與常規(guī)通道中有著顯著差異。因此,對R32在微細(xì)通道中流動(dòng)的兩相流流型、換熱特性、壓降特性研究具有重要的理論意義及實(shí)用價(jià)值。本文主要工作如下:實(shí)驗(yàn)研究了R32在內(nèi)徑1 mm和2 mm的水平微細(xì)光滑圓管內(nèi)的流動(dòng)沸騰特性,包括氣液兩相流流型、換熱特性、摩擦壓降特性。實(shí)驗(yàn)工況為質(zhì)流密度50~600kg/m2s、熱流密度10~30 kW/m2、飽和溫度10~20℃、干度0.03~0.98。得到主要結(jié)果與結(jié)論如下:得到了R32在水平微細(xì)光滑圓管中的典型流型及分布,建立了實(shí)驗(yàn)流型圖。觀察到六種典型流型:彈狀流、攪拌流、環(huán)狀流、蒸干、霧狀流、分層流。彈狀流區(qū)隨質(zhì)流密度的減小和熱流密度、飽和溫度、管徑的增大而增大;環(huán)狀流區(qū)隨質(zhì)流密度、熱流密度、飽和溫度、管徑的增大而減小;霧狀流區(qū)隨質(zhì)流密度、熱流密度、飽和溫度的增大和管徑的減小而增大�；贑osta-Patry等模型、Ong等模型、Cheng等模型、Zurcher等模型建立的流型圖對97%的實(shí)驗(yàn)流型預(yù)測準(zhǔn)確。得到了R32在水平微細(xì)光滑圓管中的換熱特性,建立了基于流型的換熱系數(shù)模型。中高質(zhì)流密度下,換熱系數(shù)隨干度增大而增大,進(jìn)入蒸干區(qū)后迅速下降,進(jìn)入霧狀流區(qū)后穩(wěn)定在較低水平;低質(zhì)流密度下,換熱系數(shù)隨干度增大而略有減小,進(jìn)入蒸干區(qū)后加速減小,進(jìn)入霧狀流區(qū)后保持穩(wěn)定。換熱系數(shù)隨質(zhì)流密度、熱流密度、飽和溫度的增大和管徑的減小而增大。起始蒸干干度隨質(zhì)流密度、熱流密度、飽和溫度的增大和管徑的減小而減小�；贙attan-Thome-Favrat等模型提出的換熱模型對96%的數(shù)據(jù)組數(shù)據(jù)預(yù)測偏差在±25%以內(nèi)。得到了R32在水平微細(xì)光滑圓管中的摩擦特性,建立了基于流型的摩擦壓降模型。中高質(zhì)流密度下,摩擦壓降隨干度增大迅速增大,進(jìn)入霧狀流區(qū)后減小;低質(zhì)流密度下,摩擦壓降隨干度增大而緩慢增大,進(jìn)入霧狀流區(qū)后小幅減小。摩擦壓降隨質(zhì)流密度、熱流密度的增大和飽和溫度、管徑的減小而增大�；贛oreno Quibén等模型提出的摩擦壓降模型對89%的數(shù)據(jù)組數(shù)據(jù)預(yù)測偏差在±25%以內(nèi)。
[Abstract]:As one of the alternative working fluids of R22, R32 has the advantages of environmental protection, safety, excellent flow and heat transfer performance, easy to obtain and engineering use. The flow boiling flow and heat transfer characteristics of micro channel are different from those of conventional channel because of their high heat transfer efficiency and are widely used in various fields. Therefore, it is of great theoretical significance and practical value to study the two-phase flow patterns, heat transfer characteristics and pressure drop characteristics of R32 flow in microchannels. The main work of this paper is as follows: the flow boiling characteristics of R32 in 1 mm and 2 mm horizontal smooth tubes are investigated experimentally, including gas-liquid two-phase flow patterns, heat transfer characteristics and friction pressure drop characteristics. The experimental conditions are as follows: mass flow density is 50 ~ 600kg / m ~ (2) s, heat flux is 1030 kW / m ~ (2), saturation temperature is 1020 鈩，

本文編號：2066602