采用双线性四边形法对螺旋管圈水冷壁和鳍片进行了剖分。将螺旋管圈水冷壁在平面上展开并划分为7个区段,采用分区段热力计算的方法确定各区段平均热负荷,通过对焓增值的计算确定各管工质在各个区段入口和出口的压力和温度。在螺旋管圈...采用双线性四边形法对螺旋管圈水冷壁和鳍片进行了剖分。将螺旋管圈水冷壁在平面上展开并划分为7个区段,采用分区段热力计算的方法确定各区段平均热负荷,通过对焓增值的计算确定各管工质在各个区段入口和出口的压力和温度。在螺旋管圈出口位置布置了温度测点,计算了在70%锅炉最大连续蒸发量(boiler maximum continuous rating,BMCR)、65%BMCR、60%BMCR3种工况下的各段校核水冷壁壁面温度,通过螺旋管圈出口处计算值与测量值的比较验证了计算模型的合理性。采用传热恶化试验关联式,预测了超临界锅炉运行在近临界压力区发生传热恶化后的最高管壁温度,为锅炉的安全运行提供了比较可靠的参考数据。展开更多
Knetics and product distributions of cellulose decomposition in near-critical water were studied with a continuous flow-type apparatus for supercritical and near-critical water reactions.The experimental temperature r...Knetics and product distributions of cellulose decomposition in near-critical water were studied with a continuous flow-type apparatus for supercritical and near-critical water reactions.The experimental temperature range was from 513?K to 583?K and residence time from 0.5?min to 1.6?min.The effects of temperature and residence time on cellulose residue were demonstrated.The apparent actiation energy evaluated was 147?kJ·mol -1 .In addition,the effects of temperature and residence time on the yield distributions of wter soluble oligomers,glucose and levulose,pyruvic aldehyde,5-hydroxymethyl furfural,furfural were described in detail.The experimental results showed that selective decomposition of cellulose in near critical water was possible.展开更多
文摘采用双线性四边形法对螺旋管圈水冷壁和鳍片进行了剖分。将螺旋管圈水冷壁在平面上展开并划分为7个区段,采用分区段热力计算的方法确定各区段平均热负荷,通过对焓增值的计算确定各管工质在各个区段入口和出口的压力和温度。在螺旋管圈出口位置布置了温度测点,计算了在70%锅炉最大连续蒸发量(boiler maximum continuous rating,BMCR)、65%BMCR、60%BMCR3种工况下的各段校核水冷壁壁面温度,通过螺旋管圈出口处计算值与测量值的比较验证了计算模型的合理性。采用传热恶化试验关联式,预测了超临界锅炉运行在近临界压力区发生传热恶化后的最高管壁温度,为锅炉的安全运行提供了比较可靠的参考数据。
文摘Knetics and product distributions of cellulose decomposition in near-critical water were studied with a continuous flow-type apparatus for supercritical and near-critical water reactions.The experimental temperature range was from 513?K to 583?K and residence time from 0.5?min to 1.6?min.The effects of temperature and residence time on cellulose residue were demonstrated.The apparent actiation energy evaluated was 147?kJ·mol -1 .In addition,the effects of temperature and residence time on the yield distributions of wter soluble oligomers,glucose and levulose,pyruvic aldehyde,5-hydroxymethyl furfural,furfural were described in detail.The experimental results showed that selective decomposition of cellulose in near critical water was possible.
