化工学报
化工學報
화공학보
JOURNAL OF CHEMICAL INDUSY AND ENGINEERING (CHINA)
2014年
12期
4699-4708
,共10页
赵艳%许伟伟%王建军%王锐%高光才%金有海
趙豔%許偉偉%王建軍%王銳%高光纔%金有海
조염%허위위%왕건군%왕예%고광재%금유해
多喷嘴射流式分离器%气固流动特性%喷嘴造旋%数值模拟%分离%流动
多噴嘴射流式分離器%氣固流動特性%噴嘴造鏇%數值模擬%分離%流動
다분취사류식분리기%기고류동특성%분취조선%수치모의%분리%류동
multi-jet cyclone%gas-solid flow characteristics%swirling based on nozzles%numerical simulation%separation%flow
基于商用软件Fluent 6.3.26,采用雷诺应力模型及DPM离散相模型并结合理论分析,对基于喷嘴造旋的射流式分离器内两相流动特性进行了模拟计算,得到了较为全面的两相流动规律与细节。结果显示,分离器内部切向速度峰值可达160 m·s?1,自由涡区的切向速度约为130 m·s?1,旋流强度明显高于传统旋风单管;沿轴向下,下行流流量逐次减少,其中稳流体顶部下行流降低最为明显,下行流减少致使颗粒卷入内旋流概率增加,分离效果下降;分离器内部局部存在顶部贴壁射流、射流区二次流及灰斗口旋涡流等次级流动;分离器压降约为27.43 kPa,喷嘴区内外旋流能耗分别为4.57 kPa(21.8%)、5.76 kPa(27.6%),稳流体区内外旋流能耗分别为5.85 kPa (27.6%)、4.01 kPa(18.9%);分离器对应的切割粒径较小,约为1.6μm,极限粒径约为10μm,符合工业应用要求;基于所建颗粒受力模型及模拟条件下,分离空间可分离的临界粒径为1~2μm,3μm及以上颗粒的逃逸浓度小于0.15 g·m?3,满足下游烟机对气流的净化要求。
基于商用軟件Fluent 6.3.26,採用雷諾應力模型及DPM離散相模型併結閤理論分析,對基于噴嘴造鏇的射流式分離器內兩相流動特性進行瞭模擬計算,得到瞭較為全麵的兩相流動規律與細節。結果顯示,分離器內部切嚮速度峰值可達160 m·s?1,自由渦區的切嚮速度約為130 m·s?1,鏇流彊度明顯高于傳統鏇風單管;沿軸嚮下,下行流流量逐次減少,其中穩流體頂部下行流降低最為明顯,下行流減少緻使顆粒捲入內鏇流概率增加,分離效果下降;分離器內部跼部存在頂部貼壁射流、射流區二次流及灰鬥口鏇渦流等次級流動;分離器壓降約為27.43 kPa,噴嘴區內外鏇流能耗分彆為4.57 kPa(21.8%)、5.76 kPa(27.6%),穩流體區內外鏇流能耗分彆為5.85 kPa (27.6%)、4.01 kPa(18.9%);分離器對應的切割粒徑較小,約為1.6μm,極限粒徑約為10μm,符閤工業應用要求;基于所建顆粒受力模型及模擬條件下,分離空間可分離的臨界粒徑為1~2μm,3μm及以上顆粒的逃逸濃度小于0.15 g·m?3,滿足下遊煙機對氣流的淨化要求。
기우상용연건Fluent 6.3.26,채용뢰낙응력모형급DPM리산상모형병결합이론분석,대기우분취조선적사류식분리기내량상류동특성진행료모의계산,득도료교위전면적량상류동규률여세절。결과현시,분리기내부절향속도봉치가체160 m·s?1,자유와구적절향속도약위130 m·s?1,선류강도명현고우전통선풍단관;연축향하,하행류류량축차감소,기중은류체정부하행류강저최위명현,하행류감소치사과립권입내선류개솔증가,분리효과하강;분리기내부국부존재정부첩벽사류、사류구이차류급회두구선와류등차급류동;분리기압강약위27.43 kPa,분취구내외선류능모분별위4.57 kPa(21.8%)、5.76 kPa(27.6%),은류체구내외선류능모분별위5.85 kPa (27.6%)、4.01 kPa(18.9%);분리기대응적절할립경교소,약위1.6μm,겁한립경약위10μm,부합공업응용요구;기우소건과립수력모형급모의조건하,분리공간가분리적림계립경위1~2μm,3μm급이상과립적도일농도소우0.15 g·m?3,만족하유연궤대기류적정화요구。
Based on Fluent 6.3.26, the gas-solids two-phase flow behavior and details of multi-jet cyclone with swirling based on nozzles, was simulated and analyzed with the Reynolds stress model (RSM) and discrete particle model (DPM). Compared with conventional cyclones, peak value of tangential velocity and average value of free-vortex reached 160 m·s?1 and 130 m·s?1 respectively, generating higher flow rotation intensity. Volume rates of downward flow kept declining along the central line, particularly in the stabilization region, inducing more chances for particles being entrained by inner upward flow with lower collection efficiency. Local roof wall-jet and circulating flow nearby the inlet of the hopper were typical secondary flows of multi-jet cyclone. Gross pressure loss of the separator was 27.43 kPa, consisting of outer swirl flow 4.57 kPa (21.8%), inner swirl flow 5.76 kPa (27.6%) in the nozzles region, and outer swirl flow 5.85 kPa (27.6%), inner swirl flow 4.01 kPa (18.9%) in the stabilization region. Particles with diameters larger than 10μm could be collected completely with cut-diameter 1.6μm, making it suitable for industrial application. Analyzing with the particle mechanical model in this paper, the critical diameter of particle that can be separated was 1—2μm and particle concentration for particles large than 3μm in the vortex finder was less than 0.15 g·m?3.