本文關(guān)鍵詞： 螺旋波紋管 強化換熱 場協(xié)同 超臨界壓力　出處：《哈爾濱工業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：強化換熱越來越多的應(yīng)用于各種換熱設(shè)備中,以達到提高換熱效率,節(jié)約能源的目的。對于螺旋波紋管內(nèi)流體的運動,由于其螺旋凹槽結(jié)構(gòu)的影響,使得管內(nèi)的流動換熱規(guī)律與光滑圓管有所不同。本文基于FLUENT軟件對不同壓力下單相水和超臨界壓力流體螺旋波紋管內(nèi)的流動和換熱進行數(shù)值模擬,對比分析了考慮粘性修正的換熱關(guān)聯(lián)式、標(biāo)準(zhǔn)k-ε湍流模型和RNG k-ε湍流模型的數(shù)值模擬結(jié)果,決定選用應(yīng)用RNG k-ε湍流模型進行數(shù)值模擬。對不同壓力下單相水在螺旋波紋管與光滑圓管的流動換熱進行對比,得出螺旋波紋管具有強化換熱的作用,研究了入口速度、溫度和螺旋波紋管的結(jié)構(gòu)參數(shù)等對徑向速度、溫度、湍動能、湍流耗散率率等的影響。并且采用綜合性能指標(biāo)PEC,熵產(chǎn),火積值耗散以及場協(xié)同的理論對強化換熱的效果進行評價分析。結(jié)果表明:在模擬所用的螺旋波紋管結(jié)構(gòu)參數(shù)下,換熱增強了1.5-2.7倍,摩擦壓力增大了1.3-4.5倍,所有結(jié)構(gòu)參數(shù)下的螺旋波紋管PEC均大于1.采用協(xié)同角,熵產(chǎn),火積耗散均能對結(jié)構(gòu)參數(shù)等對換熱的影響進行較好的預(yù)測。在超臨界壓力下,選用k-ωSST湍流模型對擬臨界溫度附近的水的流動換熱進行了數(shù)值模擬,對徑向方向上速度、溫度、以及壁面溫度,壁面?zhèn)鳠嵯禂?shù)等的分布規(guī)律進行了研究。發(fā)現(xiàn):在擬臨界溫度區(qū)域螺旋波紋管內(nèi)速度呈現(xiàn)出中心低沿壁面逐漸增高,當(dāng)靠近壁面處發(fā)生回落的變化趨勢。
[Abstract]:Enhanced heat transfer is more and more used in all kinds of heat transfer equipment to improve heat transfer efficiency and save energy. For the movement of fluid in spiral bellows due to the influence of its spiral groove structure. The flow heat transfer in the pipe is different from that in the smooth pipe. The flow and heat transfer in the spiral bellows under different pressures are simulated by FLUENT software. The numerical simulation results of heat transfer correlation, standard k- 蔚 turbulence model and RNG k- 蔚 turbulence model with viscosity correction are compared and analyzed. RNG k- 蔚 turbulence model is chosen to simulate the flow heat transfer of single-phase water in spiral corrugated tube and smooth circular tube under different pressures. It is concluded that spiral bellows can enhance heat transfer. The inlet velocity, temperature and structural parameters of spiral corrugated tube are studied on radial velocity, temperature and turbulent kinetic energy. The effects of turbulence dissipation rate and entropy production were also studied. The effect of enhanced heat transfer is evaluated and analyzed by the theory of fire product dissipation and field cooperation. The results show that the heat transfer increases by 1.5-2.7 times under the structural parameters of spiral bellows used in simulation. The friction pressure increased by 1.3-4.5 times, and the PEC of spiral bellows under all structural parameters was greater than 1.The synergistic angle and entropy production were used. The effect of structure parameters on heat transfer is well predicted. Under supercritical pressure, K- 蠅 SST turbulence model is used to simulate the flow heat transfer of water near the pseudo-critical temperature. The distribution of velocity, temperature, wall temperature, wall heat transfer coefficient and so on in radial direction are studied. It is found that the velocity of spiral bellows in the pseudo-critical temperature region increases gradually along the wall. When near the wall, the trend of falling back.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TK172

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