【正文】 設(shè)計圖標見表二。各種不同的燃料可以很容易的放到一個爐內(nèi)一同燃燒。在此期間，空氣粉塵混合物在高濃縮除塵 機的作用下，以 2530米 /秒的速度從爐子的前沿噴射。結(jié)果，以不同的速度噴射 空氣粉塵混合物和從各自不同通道出去的二級空氣（ w2/w1 = 2– 3），這些噴射物形成漩渦從而失去可以遠距噴射的能力。顯然，如果我們增加燃燒器的數(shù)量到因數(shù) 2，其當量直徑，初始噴射區(qū)域的長度 S0和他們所“服務(wù)”的區(qū)域因數(shù)將減小 2 ， 例如，當 a=， 分數(shù)β air將由 ，因此，在通過對經(jīng)過燃燒器進入爐內(nèi)混合的質(zhì)量的影響進行評估后，上述公式可以寫成：β air= nb ，在這里 nb是在一面墻上燃燒器（或空氣噴嘴）的數(shù)量，當它們被安排在一樣或相反的方式上。與此同時，我們從經(jīng)驗和計算中得知，良好的混合爐，如果我們采用大型的遠程噴射爐，可不增加頂端的損失。 不幸的是，我們必須指出，即使在目前，那些負責選擇爐具類型，數(shù)量和布局所采用的技術(shù)解決方案，還遠遠沒有得到優(yōu)化。帶有旋流的鍋爐燃燒器， a = Ff/Fb≈ 10。噴嘴吹入到爐的速度下降非常迅速，超越了最初一節(jié)的限制，壁掛式燃燒器的軸彎曲對準爐的出口。成分在爐膛內(nèi)混合的質(zhì)量嚴格上取決于數(shù)量，布局，還有從個別 爐膛和噴嘴噴射出來的流體動力，以及它們與流動的廢氣或與墻壁的相互作用。 正如一下所要展示的，第一個因素可以通過在鍋爐裝置周圍建立一些龐大的漩渦轉(zhuǎn)移大量的空氣和燃燒產(chǎn)品來實現(xiàn)。第二階段包括現(xiàn)有的現(xiàn)代化設(shè)備。 however, this entails an increase in the flow velocity and the expenditure of energy (pressure drop) in the burners with the same Fb. At the same time, we know from experience and calculations that good mixing in a furnace can be obtained without increasing the head loss if we resort to large longrange jets. This allows a much less stringent requirement to be placed on the degree of uniformity with which fuel must be distributed among the burners. Moreover, fuel may in this case be fed to the furnace location where it is required from process control considerations. For illustration purposes, we will estimate the effect the number of burners has on the mixing in a furnace at = = idem. schematically shows the plan views of two furnace chambers differing in the number of once through round nozzles (two and four) placed in a tier (on one 大連交通大學 2020 屆本科生畢業(yè)設(shè)計外文翻譯 5 side of the furnace). The furnaces have the same total outlet crosssectional areas of the nozzles (ΣFb) and the same jet velocities related to these areas (wb). The wellknown swirl furnace of the TsKTI has a design close to the furnace arrangement under consideration. According to the data of [1], the air fraction βair that characterizes the mixing and enters through once through burners into the furnace volume beneath them can be estimated using the formula βair = 1 – (3) which has been verified in the range = – for a furnace chamber equipped with two frontal once through burners. Obviously, if we increase the number of burners by a factor of 2, their equivalent diameter, the length of the initial section of jets S0 and the area they ―serve‖ will reduce by a factor of Then, for example, at = , the fraction βair will decrease from to . Thus, Eq. (3) may be written in the following form for approximately assessing the effect of once through burners on the quality of mixing in a furnace:βair = 1 – nb 39。 (iii) the fineness to which the fuel is milled. The latter case implies that a flamebed method is used along with the flame method for busting bed bustion method can be implemented in three design versions: mechanical grates with a dense bed, fluidizedbed furnaces, and spoutedbed furnaces. As will be shown below, the first factor can be made to work by setting up bulky vortices transferring large volumes of air and bustion products across and along the furnace device. If fuel is fired in a flame, the optimal method of feeding it to the furnace is to admit it to the zones near the centers of circulating vortices, a situation especially typical of highly intense furnace devices. The bustion process in these zones features a low air excess factor (α 1) and a long local time for which the ponents dwell in them, factors that help make the bustion process more stable and reduce the emission of nitrogen oxides . Also important for the control of a furnace process when solid fuel is fired is the fineness to which it is milled。this allowed a shift to be made from running the furnace in a drybottom mode to a slagtap mode and vice versa. A bottomblast furnace scheme has received rather wide use in boilers equipped with different types of burners and mills. Boilers with steam capacities ranging from 50 to 1650 t/h with such an aerodynamic scheme of furnaces manufactured by ZiO and Sibenergomash have been installed at a few power stations in Russia and abroad . We have to point out that, so far as the efficiency of furnace process control is concerned, a bination of the following two aerodynamic schemes is of special interest: the inverted scheme and the bottomblast one. The flow pattern and a calculation analysis of the furnace process in such a furnace during the bustion of lean coal are presented in [13]. Below, two other techniques for controlling the furnace process are considered. Boilers with flame–stoker furnaces have gained acceptance in industrial power engineering, devices that can be regarded to certain degree as controllable ones owing to the presence of two zones in them . Very different kinds of fuel can be jointly busted in these f