本文選題：爆震近極限傳播　切入點：受擾再起爆　出處：《國防科學技術大學》2015年博士論文　論文類型：學位論文

【摘要】：本文設計了連續(xù)旋轉爆震模型發(fā)動機及推力測量系統(tǒng),通過實驗研究與數值模擬相結合的方法,以H_2/air、H_2/O_2和CH_4/O_2為工質,開展了連續(xù)旋轉爆震波傳播機理、工作特性及其在推進中的應用研究。為深入分析連續(xù)旋轉爆震在約束構型中的波形結構和傳播特性,首先在帶有管壁約束的爆震管內開展了爆震波近極限傳播研究以及爆震波再起爆和受擾傳播的研究。發(fā)現管長影響爆震極限的準確性,應當在超過初始條件影響長度的長管內開展極限研究。速度虧損和最大速度波動在壓力逼近起爆極限時突然增長,不穩(wěn)定機制在傳播中的作用逐漸顯著;采用交錯多孔板來熄滅或者干擾爆震波的傳播,當初始壓力高于臨界壓力時,“穩(wěn)定”混合氣中的爆震起始僅發(fā)生在多孔板所能影響到的下游數倍管徑距離內。而“不穩(wěn)定”混合氣中的爆震起始不但可以發(fā)生在多孔板下游的近場,也能在數十倍管徑的遠場處以DDT方式從局部爆炸中產生;保持大致相當的堵塞比,增大孔徑到一定程度時,多孔板對爆震波傳播的擾動作用縮短了不穩(wěn)定傳播模態(tài)的傳播距離,提供了一種盡快排除不穩(wěn)定傳播模態(tài)的方法。針對連續(xù)旋轉爆震波傳播機理這一基礎問題,首次將旋轉爆震傳播模式劃分為同向傳播模式、雙波對撞模式、低速爆震模式和不穩(wěn)定傳播模式,并分析了各自形成機制。發(fā)現燃燒室壓力與出口背壓之比是影響爆震波穩(wěn)定性的重要因素。在基準構型的模型發(fā)動機中,保持當量比恒定,隨著流量增大,燃燒室內依次經歷不起爆—低速爆震模式—不穩(wěn)定爆震模式—同向傳播模式的演變,而同向模式依次出現單波模態(tài)—單/雙波混合模態(tài)—雙波(多波)模態(tài)。產生低速爆震模式和不穩(wěn)定爆震模式是由于燃燒室壓力與出口背壓之比比較低,出口處旋轉斜激波后的區(qū)域產生斜激波并被推到燃燒室內比較靠上的位置干擾噴注,引起傳播不穩(wěn)定。對于同向傳播模式,燃燒室出口排氣為超聲速,背壓對燃燒室內無影響。此外,在一些特殊構型中(比如0.2 mm寬空氣噴注喉部)或以N2吹除時,燃燒室內可能出現雙波對撞模式,此時能夠盡快建立混合層成為維持對撞的關鍵。結合實驗和數值模擬結果,深入分析了燃燒室流道長度、流道厚度、流道曲率以及軸向出口收縮等構型約束對H_2/air連續(xù)旋轉爆震波流場結構、傳播過程及推力性能的影響規(guī)律。研究表明上述構型約束對于旋轉爆震波流場結構(爆震波高度、波前壓力、穩(wěn)定性)、流場參數、流量、推力和比沖等存在不同程度的影響。分析表明:維持連續(xù)旋轉爆震波傳播所需流道長度存在最優(yōu)值,且流道曲率存在上限。在空桶燃燒室內實現并開展了以CH_4/O_2和H_2/air為工質的旋轉爆震研究。觀測了CH_4/O_2旋轉爆震的傳播過程及流場結構。對于H_2/air工質來說,流量增大導致爆震波傳播速度和峰值壓力均增大,燃燒室內發(fā)生了模態(tài)轉變,依次出現雙波對撞模態(tài)—雙波模態(tài)—單波模態(tài),前兩個模態(tài)受到了出口產物中所產生的上行斜激波的影響。研究表明環(huán)形通道不是維持旋轉爆震的必要條件,而噴注充足的可燃混合物是維持穩(wěn)定旋轉爆震的關鍵。在目前流量下,空桶內的旋轉爆震產生的推力性能不高。針對連續(xù)旋轉爆震燃燒在推進中的應用,實現了旋轉爆震模型發(fā)動機的推力測量,討論了典型模態(tài)下的推力性能及推力穩(wěn)定性。實驗表明:連續(xù)旋轉爆震波能夠長時間穩(wěn)定工作,在模型發(fā)動機中產生穩(wěn)定、可靠的推力。爆震波頭個數增多有助于推力穩(wěn)定。推力波形的振蕩頻率與爆震波高頻壓力波形存在耦合關系;隨著流量的增大,爆震波傳播模態(tài)及穩(wěn)定性發(fā)生改變,推力增長,比沖增大并趨于穩(wěn)定;當量比對爆震波傳播模態(tài)、傳播速度和推力性能均會產生影響;流量、推力和燃燒室壓力隨噴注壓力增大而快速增長。此外。隨著噴注面積的增大,需要更大流量和更高噴注壓力才能建立起維持單波頭旋轉的條件。針對旋轉爆震波較強的流量適應能力,系統(tǒng)分析了連續(xù)旋轉爆震發(fā)動機的矢量調節(jié)技術,論證了矢量調節(jié)的可行性。發(fā)現存在兩種矢量調節(jié)模式:模式I—一個周期內出現兩次推力偏轉,旋轉爆震發(fā)動機以兩倍的爆震波旋轉頻率進行矢量調節(jié)。模式II—旋轉爆震發(fā)動機一直保持向低壓噴注區(qū)方向的偏轉;面向火箭基旋轉爆震發(fā)動機的應用,分析了活性較高的H_2/O_2和CH_4/O_2混合氣中旋轉爆震波的工作特性和推力特性。因為諸多原因限制,H_2/O_2混合氣所產生的比沖指標與理論性能尚有較大差距;CH_4/O_2混合氣中的旋轉爆震比較平穩(wěn),但N2稀釋的比例對混合氣的旋轉爆震特性影響比較大。隨著總流量的增大,總比沖性能有所提升。
[Abstract]:This paper designed a continuous rotating detonation model and engine thrust measurement system and method, through the combination of experimental research and numerical simulation on H_2/air, H_2/O_2 and CH_4/O_2 as refrigerant, the continuous rotating detonation wave propagation mechanism, characteristics and application in the research work in advance. For in-depth analysis of continuous rotating detonation in the configuration constraints the structure and wave propagation characteristics in the first with a tube wall constraint detonation tube was carried out to study wave propagation in detonation and detonation and limit of disturbance propagation of detonation wave was renewed. Accuracy of the knocking limit length effect, should be in excess of the influence of initial conditions of long tube length is carried out within the limit of the maximum speed and speed loss. Fluctuation limit sudden growth in the approximation of detonation pressure, instability mechanism in spreading gradually significantly; a staggered perforated plate to knock out or interference Wave propagation, when the initial pressure is higher than the critical pressure, the detonation initiation stability in gas mixture occurs only can affect downstream of the perforated plate in the diameter range. Several times and "unstable detonation initiation" in the mixed gas can not only occur in the near field downstream of the perforated plate, but also in dozens of times the diameter of the far field a DDT generated from the local explosion; remain roughly the same blockage ratio, aperture increases to a certain extent, the porous plate shortens the propagation distance of unstable propagation mode disturbance effect on detonation wave propagation, and provides a method for removing as soon as possible unstable propagation modes on the basic. The problem of continuous rotation of the propagation mechanism of detonation wave, the rotating detonation propagation mode is divided into the same mode of transmission, double wave collision model, low detonation mode and unstable propagation mode, and analyzes their formation mechanism. It is found that burning The important factors of combustion chamber pressure and outlet pressure ratio is the impact of detonation stability. In the benchmark model of engine configuration, keep the equivalence ratio constant, as the flow increases, followed by experience - low - detonation detonation mode unstable detonation mode evolution and propagation mode to the combustion chamber, and in the same direction in single mode wave modes - Single / double wave mixed mode double wave (wave) mode. Low detonation mode and unstable detonation mode is due to the combustion chamber pressure and outlet pressure ratio is relatively low, at the outlet of the swash post shock region produced shock and pushed into the combustion on the comparison of injection position disturbance the interior, causing the spread of instability. For the same propagation mode, the combustion chamber exhaust is supersonic, pressure has no effect on the combustion chamber. In addition, in some special configurations (such as 0.2 mm wide air injection throat) or to N2 Purge, the combustion chamber may appear double wave collision model, this can become the key to maintain the mixed layer as soon as possible to establish the collision. The simulation results combined with experimental and numerical analyses of combustion chamber flow channel length, channel thickness, channel curvature and axial contraction of export configuration constraints on H_2/air continuous rotating detonation wave flow structure, influence of process and the thrust performance of communication. Research shows that the configuration constraints for rotating detonation wave flow structure (detonation wave height, wave pressure, stability), flow field parameters, flow, thrust and impulse the existence of different effects. The analysis shows that: the maintenance of continuous rotating detonation wave required channel length and the flow channel exists optimal value. In the presence of upper curvature. The empty barrel combustion chamber to realize and carry out the research of rotating detonation working with CH_4/O_2 and H_2/air. CH_4/O_2 was observed in the rotating detonation propagation process of shock And the flow structure for H_2/air refrigerant flow, increase of detonation wave speed and the peak pressure increased, the mode transformation, the combustion chamber, there are two wave impinging wave modes - Single - mode double wave mode, the first two modes are affected by the upward oblique shock wave produced in the product export. Research shows that the annular channel is not necessary to sustain rotation of the detonation, and the combustible mixture injection is the key to maintain a stable enough. In the current rotating detonation flow, rotating detonation empty bucket generated thrust performance is not high. Aiming at continuous rotating detonation combustion application in advance, the thrust measurement of rotating detonation model the engine thrust and thrust performance, discusses the stability of typical modes. The experimental results show that the continuous rotating detonation wave can work stably for a long time, in the model of the engine to generate stable, reliable Thrust head number increased. The detonation wave contributes to thrust stability. The coupling relationship between the oscillation frequency of the thrust waveform and the detonation wave high frequency pressure wave; along with the increase of flow rate, detonation propagation mode and stability of shock wave change, thrust growth, specific impulse increases and tends to be stable; equivalence ratio of detonation wave propagation velocity and thrust mode. The performance will influence; flow, thrust and combustion chamber pressure with the injection pressure increases. With the increase of rapid growth. In addition the injection area, the need for greater flow and higher spray injection pressure to maintain the established single wave head rotation condition. According to the rotating detonation wave strong flow ability, system analysis continuous vector rotating detonation engine control technology, demonstrates the feasibility of vector control. It is found that there are two kinds of vector control mode: I - a period of two times the thrust deflection, rotating detonation Shock engine vector control based on two times the detonation wave. The rotation frequency of II rotating detonation engine has been maintained to the low pressure jet deflection direction; the application of rocket based rotating detonation engine, analyzes the working characteristics and thrust characteristics of high activity of H_2/O_2 and CH_4/O_2 mixed gas in the rotating detonation wave because of many reasons. Limit of H_2/O_2 mixed gas generated by the specific impulse and the theoretical performance indexes have a large gap; rotating detonation CH_4/O_2 gas mixture are relatively stable, but the effects of N2 dilution ratio on rotating detonation characteristics of mixed gas is relatively large. With the increase of the total flow, the total specific impulse performance has improved.

【學位授予單位】：國防科學技術大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：V430
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本文編號：1585962