【摘要】：為了實(shí)現(xiàn)近零污染排放,在整體煤氣化聯(lián)合循環(huán)系統(tǒng)中集成燃燒前碳捕集技術(shù)被認(rèn)為是可行性最高的方法之一。此時(shí)氫氣或富氫氣體將作為燃料送入燃?xì)廨啓C(jī)中,因此首先需要發(fā)展氫燃機(jī)技術(shù)。然而回火,尤其是燃燒誘導(dǎo)渦破碎(Combustion Induced Vortex Breakdown, CT WB)回火阻礙了氫燃機(jī)的發(fā)展。本文將數(shù)值模擬與實(shí)驗(yàn)結(jié)合起來,針對氫燃料旋流預(yù)混火焰的CIVB回火特性進(jìn)行了分析和探討。首先收集了氫燃料燃燒特性數(shù)據(jù)并篩選出合適的化學(xué)反應(yīng)機(jī)理和數(shù)值模擬計(jì)算模型,為進(jìn)一步開展CIVB回火模擬工作打下了基礎(chǔ)。隨后,采用正交試驗(yàn)設(shè)計(jì)方法進(jìn)行數(shù)值試驗(yàn)方案的安排,通過對數(shù)值模擬結(jié)果的分析,確定了影響CIVB回火的各參數(shù)的主次排序及影響趨勢,并結(jié)合方差分析方法指出了具有顯著影響的參數(shù)。然后開展了相關(guān)的實(shí)驗(yàn)研究工作,驗(yàn)證了數(shù)值模擬結(jié)果的可靠性。此外,在數(shù)值模擬過程中通過分析位于預(yù)混段內(nèi)靠近中心體壁面(對于有中心體的結(jié)構(gòu))或者預(yù)混段中心線(對于無中心體的結(jié)構(gòu))附近上下游兩點(diǎn)的軸向速度、壓力、溫度和切向渦量等物理量隨著當(dāng)量比的變化趨勢,澄清了CIVB回火發(fā)生的過程,并提出了CIVB回火的機(jī)理。最后應(yīng)用上述研究結(jié)果提出了兩種抑制CIVB回火的方法。本文的主要結(jié)論如下：1.多參數(shù)對CIVB回火影響的數(shù)值研究綜合分析結(jié)構(gòu)參數(shù)和運(yùn)行參數(shù)對CNB回火臨界當(dāng)量比的影響,按照其影響程度的主次排序?yàn)椋盒髌鹘Y(jié)構(gòu)預(yù)混段結(jié)構(gòu)空氣入口溫度燃料組分火焰筒結(jié)構(gòu)質(zhì)量流量。其中,前四個(gè)因素對CNB回火具有高度顯著的影響,是在設(shè)計(jì)過程中需要重點(diǎn)考慮的因素。數(shù)值模擬結(jié)果證明各個(gè)參數(shù)是通過改變流場分布和火焰特性而作用于CIVB回火。根據(jù)多參數(shù)分析的結(jié)果將現(xiàn)有僅適用于特定幾何結(jié)構(gòu)的時(shí)間尺度模型擴(kuò)展至變幾何結(jié)構(gòu)。這樣,通過一次試驗(yàn)確定初始結(jié)構(gòu)的熄火常數(shù)Cq后,便可計(jì)算出運(yùn)行條件和幾何結(jié)構(gòu)變化時(shí)的回火臨界當(dāng)量比,而無需進(jìn)行額外的試驗(yàn),對燃燒室的改進(jìn)設(shè)計(jì)具有定量的指導(dǎo)意義。2.多參數(shù)對CIVB回火影響的實(shí)驗(yàn)研究實(shí)驗(yàn)結(jié)果證實(shí)了通過數(shù)值模擬得到的預(yù)混段結(jié)構(gòu)、質(zhì)量流量和燃料組分對CIVB回火影響程度排序的可靠性。此外還證實(shí)了擴(kuò)展的時(shí)間尺度模型的確可適用于不同的預(yù)混段結(jié)構(gòu),并發(fā)現(xiàn)熄火常數(shù)Cq正比于空氣質(zhì)量流量。3.CIVB回火發(fā)生過程和機(jī)理的研究CIVB回火過程可被分為三個(gè)階段：火焰向上游傳播、渦破碎和火焰穩(wěn)定。這三個(gè)階段可分別采用一維守恒模型、渦量輸運(yùn)方程模型和時(shí)間尺度模型進(jìn)行描述。這三個(gè)階段的劃分、一維守恒模型和時(shí)間尺度模型都具有普遍適用性,與所采用的燃料組分和幾何結(jié)構(gòu)無關(guān)。然而,渦破碎發(fā)生過程以及對應(yīng)的渦量輸運(yùn)方程模型則與幾何結(jié)構(gòu)(中心體)密切相關(guān)。當(dāng)有中心體存在時(shí),渦破碎的過程為：由于旋流及粘性作用預(yù)混段內(nèi)靠近中心體區(qū)域下游與上游位置間的壓差增大,使得局部軸向速度降低、靜壓增大,從而促進(jìn)跡線的發(fā)散,切向渦量開始起作用。切向渦量誘導(dǎo)出的速度始終與軸向速度相反,而軸向速度的大小又會(huì)影響切向渦量值,兩者之間的相互作用會(huì)建立一個(gè)新的平衡狀態(tài)。此時(shí),軸向速度達(dá)到最小值、靜壓和壓差達(dá)到最大值,隨后發(fā)生渦破碎。當(dāng)無中心體存在時(shí),渦破碎的發(fā)生過程與有中心體的結(jié)構(gòu)基本一致,只是切向渦量和軸向速度之間是相互促進(jìn)的,只有當(dāng)兩者同時(shí)達(dá)到最小值時(shí)才會(huì)發(fā)生渦破碎。在此過程中沒有建立新的平衡態(tài)。渦破碎發(fā)生的過程構(gòu)成CIVB回火發(fā)生的流場路線。火焰向上游傳播并穩(wěn)定在破碎的渦內(nèi)構(gòu)成CIVB回火發(fā)生的火焰路線。發(fā)生渦破碎的不可逆能量損失使得回火驅(qū)動(dòng)力壓差顯著降低,無力再維持流場路線和火焰路線的改變,構(gòu)成CIVB回火發(fā)生的反饋路線。三條路線緊密地連接在一起,共同促進(jìn)CIVB回火的發(fā)生。4.CIVB回火控制方法的提出根據(jù)CIVB回火多參數(shù)分析的結(jié)論,可以通過調(diào)整預(yù)混段結(jié)構(gòu)和旋流器結(jié)構(gòu)實(shí)現(xiàn)CIVB回火的被動(dòng)控制。也就是說,對一個(gè)初始設(shè)計(jì)方案通過試驗(yàn)確定其熄火常數(shù)Cq后便可根據(jù)Cq和預(yù)期的回火臨界當(dāng)量比計(jì)算出所需要的幾何結(jié)構(gòu)參數(shù)。此外,基于CIVB回火發(fā)生的機(jī)理,提出了一種對CIVB回火進(jìn)行主動(dòng)控制的方法,即在預(yù)混段最前端且靠近中心體壁面區(qū)域引入一股額外的氣流來降低中心體壁面附近下游與上游間的壓差,從而抑制CIVB回火。通過比較這兩種方法實(shí)施的難度和可靠性,本文推薦現(xiàn)階段最好采用被動(dòng)控制方法,而主動(dòng)控制方法可以作為下一階段的研究目標(biāo)。5.對氫燃料旋流貧預(yù)混燃燒室初步設(shè)計(jì)的建議與傳統(tǒng)的天然氣燃料旋流貧預(yù)混燃燒室相比,在進(jìn)行氫燃料燃燒室初步設(shè)計(jì)時(shí)應(yīng)：(1)同時(shí)驗(yàn)證冷態(tài)速度場和溫度場；(2)特別注意旋流器結(jié)構(gòu)和預(yù)混段結(jié)構(gòu)參數(shù)的選取,盡量采用較低的旋流數(shù)；(3)避免在燃料噴射區(qū)域或旋流器葉片尾緣區(qū)域形成尾跡渦。綜上所述,本文通過數(shù)值模擬結(jié)合正交試驗(yàn)設(shè)計(jì)方法掌握了燃燒室?guī)缀谓Y(jié)構(gòu)參數(shù)和運(yùn)行參數(shù)對CIVB回火影響的規(guī)律,闡明了CIVB回火發(fā)生的過程和機(jī)理,并據(jù)此提出了CIVB回火的控制方法,給出了氫燃料旋流貧預(yù)混燃燒室在初步設(shè)計(jì)時(shí)的建議。
[Abstract]:In order to achieve near-zero pollution emissions, integrated pre-combustion carbon capture technology is considered one of the most feasible methods in the integrated coal gasification combined cycle system. At this time, hydrogen or hydrogen-rich gases will be fed into the gas turbine as fuel, so hydrogen turbine technology needs to be developed first. However, tempering, especially Combustion-Induced Vortex Breakage (CIVBR) is one of the most feasible methods. On-Induced Vortex Breakdown (CT WB) tempering hinders the development of hydrogen-fired engines. Combining numerical simulation with experiment, the tempering characteristics of hydrogen-fired swirl premixed flame are analyzed and discussed. Firstly, the combustion characteristics of hydrogen fuel are collected and the appropriate chemical reaction mechanism and numerical simulation model are selected. Then, the orthogonal experimental design method is used to arrange the numerical test scheme. Through the analysis of the numerical simulation results, the primary and secondary order of the parameters affecting the CIVB tempering and the influence trend are determined, and the parameters which have significant influence are pointed out with the method of variance analysis. In addition, the axial velocities, pressures, temperatures and temperatures of the upstream and downstream points located in the premixed section near the center wall (for the structure with a center) or the center line of the premixed section (for the structure without a center) are analyzed during the numerical simulation. The tangential vorticity and other physical quantities change with the equivalent ratio, clarifying the process of CIVB tempering, and putting forward the mechanism of CIVB tempering. Finally, two methods of restraining CIVB tempering are put forward based on the above research results. The main conclusions of this paper are as follows: 1. Numerical study on the influence of multi-parameters on CIVB tempering comprehensively analyzes the structural parameters and transportation. The influence of row parameters on the critical equivalence ratio of CNB tempering is in the order of the air inlet temperature of the premixed section of the swirler structure and the mass flow rate of the fuel composition flame tube structure. The results show that each parameter acts on CIVB tempering by changing the flow field distribution and flame characteristics. According to the results of the multi-parameter analysis, the existing time-scale models which are only suitable for specific geometric structures are extended to variable geometric structures. The critical equivalence ratio of tempering when the geometry of the combustor changes without additional tests is of quantitative significance for improving the design of the combustor. In addition, the reliability of the extended time-scale model is verified. It is found that the quenching constant Cq is proportional to the air mass flow rate. 3. The CIVB tempering process can be divided into three stages: flame propagation upstream, vortex breaking and flame stability. One-dimensional conservation model, vorticity transport equation model and time-scale model can be used to describe the three stages respectively. The three stages, one-dimensional conservation model and time-scale model, have universal applicability and are independent of the fuel composition and geometric structure used. However, the process of vortex breakup and the corresponding vorticity transport equation model When there is a central body, the process of vortex breakup is that the local axial velocity decreases and the static pressure increases due to the pressure difference between the downstream and the upstream positions near the central body region in the premixed section due to the swirl and viscous action, which promotes the divergence of the trace and the tangential vorticity begins to take effect. The velocity induced by vorticity is always opposite to the axial velocity, and the magnitude of the axial velocity will affect the tangential vorticity. The interaction between the two will create a new equilibrium state. The vortex breakage occurs only when the tangential vorticity and axial velocity reach the minimum value simultaneously. No new equilibrium state is established in the process. The process of vortex breakage forms the flow field route of CIVB tempering. The irreversible energy loss caused by the vortex breakage makes the driving force pressure drop remarkably reduced, and the flow field and flame path can not be maintained to form the feedback route of CIVB tempering. According to the conclusion of multi-parameter analysis of CIVB tempering, the passive control of CIVB tempering can be realized by adjusting the structure of premixed section and cyclone. That is to say, after determining the extinguishing constant Cq of an initial design scheme through experiment, the required Cq and the expected critical equivalent ratio of tempering can be calculated. In addition, based on the mechanism of CIVB tempering, a method of active control of CIVB tempering is proposed, that is, introducing an additional air stream into the front of the premixed section and near the center wall to reduce the pressure difference between the upstream and downstream near the center wall to suppress the CIVB tempering. It is recommended that the passive control method should be adopted at the present stage, and the active control method can be used as the research objective in the next stage. 5. Proposals for preliminary design of hydrogen fuel swirl lean premixed combustor are compared with the traditional natural gas fuel swirl lean premixed combustor. The design should: (1) verify the cold velocity and temperature fields at the same time; (2) pay special attention to the selection of the structure parameters of the cyclone and the premixed section, and try to use a lower number of swirls; (3) avoid the formation of wake vortices in the fuel injection region or the trailing edge region of the cyclone blade. The influence of combustion chamber geometry parameters and operation parameters on CIVB tempering is mastered. The process and mechanism of CIVB tempering are expounded. The control method of CIVB tempering is put forward. Suggestions for preliminary design of hydrogen swirl lean premixed combustion chamber are given.
【學(xué)位授予單位】：中國科學(xué)院研究生院(工程熱物理研究所)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TK16

【參考文獻(xiàn)】

相關(guān)期刊論文 前3條

1 ;Measurement of laminar burning velocities and analysis of flame stabilities for hydrogen-air-diluent premixed mixtures[J];Chinese Science Bulletin;2009年05期

2 施_g翰;;M251S型燃?xì)廨啓C(jī)的技術(shù)特性及結(jié)構(gòu)特點(diǎn)[J];熱力透平;2008年03期

3 楊福忠;;M251S型聯(lián)合循環(huán)發(fā)電機(jī)組在太鋼的應(yīng)用[J];山西冶金;2011年03期

相關(guān)碩士學(xué)位論文 前1條

1 白小磊;基于定容燃燒彈的甲烷摻氫燃燒特性研究[D];北京工業(yè)大學(xué);2011年

，

本文編號(hào)：2223124