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  本文關鍵詞：鋼軌異型坯高壓水除鱗過程中沖擊及換熱特性研究　出處：《燕山大學》2015年碩士論文　論文類型：學位論文

  更多相關文章： 鋼軌異型坯 除鱗 水壓 溫度場 換熱系數(shù)

【摘要】：鋼軌的表面質量、平直度、強度等因素決定著鋼軌的使用性能和壽命。尤其是在高速鐵路的應用方面,為保證鐵路系統(tǒng)安全、穩(wěn)定運行,對鋼軌的制造精度和表面質量提出了更高的要求。現(xiàn)代鋼軌的生產(chǎn)主要采用的是萬能軋制的方法,在萬能軋制的過程中,對鋼軌異型坯進行高壓水除鱗是必不可少的一步。除鱗效果的好壞,直接影響著鋼軌的萬能軋制過程,進而影響整個鋼軌產(chǎn)品的質量。所以本文旨研究在鋼軌除鱗過程中的一些特性,從理論上分析其沖擊和換熱的情況。本文首先用數(shù)值模擬的方法解決了鋼軌異型坯在受高壓水沖擊作用下的除鱗壓力的分布問題。由于鋼軌斷面形狀復雜,沖擊受力情況難以預測,實驗法存在著較大的局限性。我們通過模型的合理簡化利用Fluent軟件由淺入深地分析鋼軌異型斷面不同部分的沖擊壓力分布�？偟膩碚f,這種壓力分布在噴嘴中心處最大,向邊緣處逐漸減小;同時受斷面形狀和噴嘴布置情況影響較大。其次,本文采用同樣的模型并開啟能量方程,研究該物理過程中的換熱性能。借助傳熱學的基本理論和數(shù)值模擬的方法,得到了鋼軌異型坯表面附近的溫度場分布并分析了其形成原因。溫度場的分布和壓力場分布正好相反,由于射流中心處的換熱劇烈,所以中心處的溫度最低,向兩側逐漸升高;受斷面形狀和噴嘴布置影響更加明顯。最后,作者研究了一種簡單的換熱系數(shù)求解模型。利用鋼軌表面以下深度為2mm處的測點溫度變化曲線,通過C語言編程求解鋼軌表面的換熱系數(shù)分布。換熱系數(shù)和沖擊壓力部分情況類似,沖擊壓力越大的地方換熱越劇烈,其換熱系數(shù)也就越大。同時,這一過程受時間變化影響較大,我們可以合理的選取時間步長以保證求解精度。
[Abstract]:The surface quality, flatness and strength of rail determine the performance and service life of rail, especially in the application of high-speed railway, in order to ensure the safety and stability of railway system. The manufacturing precision and surface quality of rail are required higher. The main method of modern rail production is universal rolling, in the process of universal rolling. High pressure water descaling is an essential step for the special slab of rail. The effect of descaling has a direct impact on the universal rolling process of rail. And then affect the quality of the whole rail product, so this paper aims to study some characteristics in the process of rail descaling. In this paper, firstly, numerical simulation is used to solve the problem of the descaling pressure distribution of rail special-shaped billet under the action of high pressure water shock. The shape of rail section is complex. The impact force is difficult to predict. Through the reasonable simplification of the model, we use Fluent software to analyze the impact pressure distribution of different parts of the abnormal section of rail from shallow to deep. The pressure distribution is maximum at the center of the nozzle and gradually decreases to the edge. At the same time, it is greatly affected by the shape of the section and the configuration of the nozzle. Secondly, the same model is adopted and the energy equation is opened. The heat transfer performance in the physical process is studied by means of the basic theory of heat transfer and the method of numerical simulation. The distribution of temperature field near the surface of the slab is obtained and the reason is analyzed. The distribution of temperature field is opposite to that of pressure field. The temperature at the center of the jet is the lowest because of the intense heat transfer at the center of the jet. Increasing to both sides; The influence of section shape and nozzle arrangement is more obvious. Finally, the author studies a simple heat transfer coefficient solution model. The temperature change curve of measuring points with depth of 2 mm below the surface of rail is used. The distribution of heat transfer coefficient on rail surface is solved by C language programming. The heat transfer coefficient is similar to that of impact pressure. The greater the impact pressure, the more intense the heat transfer coefficient is. At the same time, the higher the impact pressure is, the greater the heat transfer coefficient is. This process is greatly affected by the time change, we can reasonably select the time step to ensure the accuracy of the solution.
【學位授予單位】：燕山大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TG335

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本文編號：1393010