本文選題：防爆柴油機　切入點：排氣系統(tǒng)　出處：《中北大學》2015年碩士論文　論文類型：學位論文

【摘要】：防爆柴油機排氣系統(tǒng)主要由排氣歧管、排氣波紋管、廢氣處理裝置、阻火器和排氣管組成。其中，排氣阻火器是保證防爆柴油機隔爆性能的必備裝置，能防止排氣系統(tǒng)回火、竄火，但同時會使排氣背壓上升，嚴重影響防爆柴油機的排氣性能；因此，研究阻火器的流場與結(jié)構(gòu)形式，對提高防爆柴油機的綜合性能具有實際工程意義。本文針對6100防爆柴油機排氣阻火器進行研究，在保證隔爆能力的基礎(chǔ)上，從降低排氣阻力的角度出發(fā)，，設(shè)計了一款結(jié)構(gòu)新型的阻火器，主要研究內(nèi)容和成果如下： （1）對近十年來國內(nèi)外的阻火器專利信息進行了分析，了解當前國內(nèi)外阻火器的先進技術(shù)、理論，并由此對阻火器未來的發(fā)展方向做出預(yù)測。 （2）對平板阻火器隔爆實驗做數(shù)值仿真，驗證了本文所用的計算方法的可行性。通過對實驗裝置的幾何模型做適當簡化，采用GAMBIT建立其二維模型；通過FLUENT對網(wǎng)格做獨立性分析，結(jié)合實際情況確定了定解條件，對封閉系統(tǒng)內(nèi)甲烷/空氣預(yù)混氣體的點燃及爆炸過程進行模擬，將模擬結(jié)果與實驗計算進行對比，結(jié)果發(fā)現(xiàn)，二者大致相符，說明本文所采用的數(shù)值計算方法是可行的。 （3）對平板阻火器及波紋阻火器內(nèi)部流場進行模擬，比較不同結(jié)構(gòu)形式阻火器的隔爆性能與流通能力，獲得結(jié)構(gòu)形式對阻火器性能的影響規(guī)律：阻火器狹縫尺寸越大、自由面積率越高，隔爆性能便越差；火焰的淬熄距離與阻火器的自由面積率不成線性關(guān)系；阻火器流通能力的優(yōu)劣正好跟它的隔爆性能相反，二者此消彼長，相互矛盾。 （4）參考SCR催化器載體的結(jié)構(gòu)提出方格孔阻火器，并對其做流場分析；為方格孔阻火層確定相關(guān)尺寸，利用流固耦合方法，算出氣流經(jīng)過阻火器時柵欄片的變形量，并根據(jù)煤炭行業(yè)的相關(guān)規(guī)定：柵欄片的平面度不能大于0.15mm，確定柵欄片的厚度為0.4mm；對方格孔做流場分析，要求方格孔須滿足隔爆性能，并盡量降低排氣阻力，按這兩個要求確定方格孔的尺寸為1.2mm×1.2mm，阻火器在氣流方向上的厚度為65mm。 （5）對最終設(shè)計好的方格孔阻火器做三維流場分析，并與平板式、波紋式阻火器的性能進行比較，最終發(fā)現(xiàn)，方格孔阻火器阻火性能與波紋阻火器的相差無幾，且流通性能要優(yōu)于波紋阻火器的流通性能。 本文設(shè)計的方格孔阻火器，參考了SCR催化器載體的結(jié)構(gòu)，這也意味著，催化器載體經(jīng)過適當?shù)恼{(diào)整后也可具備隔爆能力。因此，本文的研究，使催化器與阻火器實現(xiàn)一體化成為可能，從而可精簡防爆柴油機排氣系統(tǒng)組成，降低排氣阻力，達到提高防爆柴油機性能的目的，這對防爆柴油機的防爆技術(shù)及尾氣的凈化均有理論與工程意義。
[Abstract]:The exhaust system of explosion-proof diesel engine is mainly composed of exhaust manifold, exhaust corrugated tube, exhaust gas treatment device, fire arrester and exhaust pipe. But at the same time, the exhaust back pressure will rise, and the exhaust performance of explosion-proof diesel engine will be seriously affected. Therefore, the flow field and structure of the igniter are studied. It is of practical engineering significance to improve the comprehensive performance of explosion-proof diesel engine. In this paper, the exhaust arrester of 6100 explosion-proof diesel engine is studied. On the basis of ensuring the flameproof capability, the exhaust resistance is reduced. A new type of fire arrester is designed. The main research contents and results are as follows:. This paper analyzes the patent information of fire arresters at home and abroad in recent ten years, and finds out the advanced technology and theory of fire arresters at home and abroad, and predicts the future development direction of fire arresters. 2) numerical simulation on flameproof flat-plate fire arrester is made, which verifies the feasibility of the calculation method used in this paper. Through the proper simplification of the geometric model of the experimental device, the two-dimensional model is established by using GAMBIT, and the independence of the mesh is analyzed by FLUENT. Combined with the actual situation, the conditions of the fixed solution are determined, and the ignition and explosion process of the methane / air premixed gas in the closed system is simulated. The simulation results are compared with the experimental calculation. It is found that the results are roughly consistent with each other. It is shown that the numerical method used in this paper is feasible. 3) the internal flow field of flat and corrugated fire arresters is simulated, and the flameproof performance and circulation ability of different structural types are compared. The influence of structural forms on the performance of fire arresters is obtained: the bigger the slit size is, The higher the free area ratio is, the worse the flameproof performance is. The quenching distance of flame does not have a linear relationship with the free area ratio of the flame arrester. The flow ability of the flame arrester is just opposite to its flameproof performance. (4) referring to the structure of the carrier of SCR catalytic converters, this paper puts forward a grid pore arrester and analyzes its flow field, determines the relevant dimensions for the square hole fire arrester layer, and calculates the deformation of the palisade when the airflow passes through the arrester by using the fluid-solid coupling method. According to the relevant regulations of the coal industry, the planeness of the palisade plate can not be greater than 0.15 mm, and the thickness of the palisade slice is determined to be 0.4mm.The flow field analysis of the other hole requires that the square hole must meet the flameproof performance and reduce the exhaust resistance as far as possible. According to these two requirements, the size of the square hole is 1.2mm 脳 1.2mm, and the thickness of the igniter in the direction of air flow is 65mm. Finally, it is found that the fire resistance performance of square hole fire arrester is no different from that of corrugated fire arrester, compared with the performance of flat plate type and corrugated type fire arrester, and the three dimensional flow field analysis of the finally designed square hole fire arrester is compared with that of flat plate type and corrugated type fire arrester. The circulation performance of corrugated firearm is better than that of corrugated firearm. The lattice orifice arrester designed in this paper refers to the structure of SCR catalytic converter carrier, which means that the catalyst carrier can also have flameproof ability after proper adjustment. It is possible to realize the integration of catalytic converters and fire arresters so as to simplify the composition of the exhaust system of explosion-proof diesel engines, reduce the exhaust resistance, and achieve the purpose of improving the performance of explosion-proof diesel engines. This is of theoretical and engineering significance to explosion proof technology and exhaust gas purification of explosion-proof diesel engine.
【學位授予單位】：中北大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TK423

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