| In the face of increasingly tense energy situation and serious environmental pollu-tion, biomass methanol fuel as a new kind of renewable clean energy, has been widelyresearched and applied. However, its calorific value is low and the latent heat of va-porization is large, temperature of direct combustion and the combustion efficiency islow, which seriously hinder the alcohol methanol fuel widely application. Therefore, theresearching and designing a new kind of technology of high combustion efficiency forbiomass methanol fuel have important practical significance and application value.Biomass methanol fuel atuo-adaptive air distribution ejecting combustion technol-ogy and ejecting burner are proposed in this paper. The liquid alcohol fuel is vaporized,and then using the vaporized fuel gas ejects air required for complete combustion, andlast sprays into the combustion chamber to combust. The designed power of biomassmethanol fuel ejecting burner is100kW, and the atuo-adaptive air distribution charac-teristics of burner are researched by numerical simulation. The influence of the fuelnozzle installation location, the ratio α of ejector throat diameter and the nozzle exitdiameter, the ejector working pressure and the back pressure of ejector on the Mole AirEjecting Ratio (MAER) is analyzed, and various factors impact on the MAER are found.Original design parameters are optimized by atuo-adaptive air distribution characteris-tics. The optimal structure parameters of burner are obtained to realize that burner sup-ply the air atuo-adaptively. Hot numerical simulation is made to research the optimumparameters. Finally using the experimental method is aimed to research atuo-adaptiveair distribution characteristics for the optimal structure of burner when the burner powerchanges from25%to120%. The burner’s actual MAER, combustion efficiency andcombustion temperature distribution features have been obtained. The comparativeanalysis of theoretical research results and experimental research results has been car-ried.The significant results are listed as following.(1) The structure parameters of bio-mass methanol fuel ejecting burner have a great effect on MAER and auto-adaptive airdistribution characteristics of burner. Main contents are as follow: When the ejector fuelnozzle position changes between the ejector throat and the inhaled segment entrance ataxial direction, the MAER keeps almost unchanged. When nozzle inserts into the throator leaves the inhaled segment entrance, the MAER is sharp changed. With the ratio α of the throat diameter and the nozzle outlet diameter increasing, the MAER is increased,after α=8.5, the MAER remain steady. With the increase of ejector work pressure, theMAER remain unchanged. However, the MAER is decreased when the ejecting burnerback pressure increases. The burner cannot work normally when ejecting burner backpressure is more than250Pa.(2) Research obtained the best structure parameters andproportion of biomass methanol fuel ejecting burner to achieve auto-adaptive air distri-bution function of the burner. The optimal structure of each key parameter keep propor-tion is as follow: the proportion of inhaled segment entrance diameter of ejector, throatdiameter, diffuser outlet diameter, nozzle diameter and combustion chamber diameter isD_X: D_H: D_D: D_P: D_C=2:1:1.9:1.5,5.7; The proportion of the length of ejector mixingsection, diffuser, contraction, and the combustion chamber is L_H: L_D: L_P: L_C=5:5:1:10.(3) The biomass methanol fuel ejecting burner can realize auto-adaptive air distributionand combust stably, and combustion efficiency is above99.2%on optimal structure ofburner when burner power changes greatly. For the best structure proportion ofauto-adaptive air distribution ejecting burner, the MAER change rate is less than6.3%,when the burner power changes from25%to120%. The ejecting burner can distributeair automatically and combust stably. When burner power changes from25%to120%,the combustion efficiency is more than99.2%, so the combustion efficiency is improvedsignificantly. When burner power is less than40%, the combustion temperature is in-creased as the burner power raises, when the power is more than40%, the combustiontemperature is basically stable at1650K. |
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