<p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">60</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、某循环热源温度为<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="527" unitname="℃" wst="on"></chmetcnv><span lang="EN-US">527</span>℃<chmetcnv></chmetcnv>,冷源温度为<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="27" unitname="℃" wst="on"></chmetcnv><span lang="EN-US">27</span>℃<chmetcnv></chmetcnv>,在此温度范围内循环可能达到的最大热效率是多少?<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:解:已知<span lang="EN-US">T1=273+527=800K<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">T2=273+27=300K<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">η最大<span lang="EN-US">=</span>η卡<span lang="EN-US">=1-T2/T1=1-300/800=0.625<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">61</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、温度为<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="10" unitname="℃" wst="on"></chmetcnv><span lang="EN-US">10</span>℃<chmetcnv></chmetcnv>的水在管道中流动,管道直径<span lang="EN-US">d=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="200" unitname="mm" wst="on"></chmetcnv>200mm<chmetcnv></chmetcnv></span>,流量<span lang="EN-US">Q=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="100" unitname="m3" wst="on"></chmetcnv>100m3<chmetcnv></chmetcnv>/H,<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="10" unitname="℃" wst="on"></chmetcnv>10<span lang="EN-US"><span lang="EN-US">℃</span></span><chmetcnv></chmetcnv><span lang="EN-US">水的运动粘度V=1.306</span></span>×<span lang="EN-US">10<chmetcnv tcsc="0" numbertype="1" negative="True" hasspace="False" sourcevalue="6" unitname="m2" wst="on"></chmetcnv>-6m2<chmetcnv></chmetcnv>/s</span>,求水的流动状态是层流还是紊流:<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:解:管道中平均流速<span lang="EN-US">:C=Q/(</span>π<span lang="EN-US">d2/4)=4Q/</span>π<span lang="EN-US">d2=4</span>×<span lang="EN-US">100/3600</span>×<span lang="EN-US">3.14</span>×<span lang="EN-US">0.22=0.885(m/s)<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">雷诺数<span lang="EN-US">Re=cd/V=0.885</span>×<span lang="EN-US">0.2/1.306</span>×<span lang="EN-US">10-6=13553<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">∵<span lang="EN-US">13553>2300,</span>∴此流动为紊流<span lang="EN-US">.<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">62</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、已知主汽压<span lang="EN-US">1=88.3bar</span>(绝以压力)和<span lang="EN-US">t1=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="500" unitname="℃" wst="on"></chmetcnv>500<span lang="EN-US"><span lang="EN-US">℃</span></span><chmetcnv></chmetcnv><span lang="EN-US">,功率为2.5</span></span>万千瓦,凝汽器中的<span lang="EN-US">2=0.03924,</span>试计算朗肯循环时的热效率,汽耗率,热耗率及每小时的汽耗量和热耗量。<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">(由<span lang="EN-US">i-s</span>图查得<span lang="EN-US">i1=3387kJ/kg,i2=2009.7KJ/kg</span>)<span lang="EN-US"><p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:热效率:η<span lang="EN-US">=</span>(<span lang="EN-US">i1-i2</span>)<span lang="EN-US">/</span>(<span lang="EN-US">i1-i2'</span>)<span lang="EN-US">=0.421<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">热耗率:<span lang="EN-US">q=3600/</span>η<span lang="EN-US">=8551(kg/kwh)<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">汽耗率:<span lang="EN-US">d=3600/</span>(<span lang="EN-US">i1-i2</span>)<span lang="EN-US">=2.614(kg/kwh)<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">热耗量:<span lang="EN-US">Q=Nq=2.134_10 (KJ/h)<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">汽耗量:<span lang="EN-US">D=Nd=65250(kg/h)<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">63</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、水流过一管长<span lang="EN-US">L=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="5" unitname="m" wst="on"></chmetcnv>5m<chmetcnv></chmetcnv></span>的加热器,从<span lang="EN-US">t</span>水<span lang="EN-US">'=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="25" unitname="℃" wst="on"></chmetcnv>25<span lang="EN-US"><span lang="EN-US">℃</span></span><chmetcnv></chmetcnv>,</span>加热到<span lang="EN-US">t</span>水<span lang="EN-US">'=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="35" unitname="℃" wst="on"></chmetcnv>35<span lang="EN-US"><span lang="EN-US">℃</span></span><chmetcnv></chmetcnv><span lang="EN-US">,管内径d=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="20" unitname="mm" wst="on"></chmetcnv>20mm<chmetcnv></chmetcnv></span></span>,管壁平均温度<span lang="EN-US">t=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="36" unitname="℃" wst="on"></chmetcnv>36<span lang="EN-US"><span lang="EN-US">℃</span></span><chmetcnv></chmetcnv>,</span>水与壁的对流换热系数α<span lang="EN-US">=8130w/</span>(<span lang="EN-US">m </span>℃)<span lang="EN-US">,</span>求水与壁的换热量。<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:水的平均温度<span lang="EN-US">:t=1/2(t'+t")=30<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">管子表面积:<span lang="EN-US">F=</span>π<span lang="EN-US">dl=0.314(m )<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">换热量:<span lang="EN-US">Q=</span>α<span lang="EN-US">(t</span>壁<span lang="EN-US">-t</span>水<span lang="EN-US">)F=15316.92(w)<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">64</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、冷油器入口油温<span lang="EN-US">t1=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="55" unitname="℃" wst="on"></chmetcnv>55<span lang="EN-US"><span lang="EN-US">℃</span></span><chmetcnv></chmetcnv>,</span>出口油温<span lang="EN-US">t2=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="40" unitname="℃" wst="on"></chmetcnv>40<span lang="EN-US"><span lang="EN-US">℃</span></span><chmetcnv></chmetcnv>,</span>油的流量<span lang="EN-US">Q=50t/h</span>,求油每小时放热量。(油的比热<span lang="EN-US">CP=1.9887kJ/kg</span>℃)<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:解:<span lang="EN-US">Q=mCp(t1-t2)=50 1000 1.9887 (55-40)=1491525(kJ/h)<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">65</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、已知凝汽器入口温度<span lang="EN-US">t=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="18" unitname="℃" wst="on"></chmetcnv>18<span lang="EN-US"><span lang="EN-US">℃</span></span><chmetcnv></chmetcnv>,</span>冷却水温升Δ<span lang="EN-US">t=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="10" unitname="℃" wst="on"></chmetcnv>10<span lang="EN-US"><span lang="EN-US">℃</span></span><chmetcnv></chmetcnv>,</span>低压缸排汽温度<span lang="EN-US">t'=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="32.5" unitname="℃" wst="on"></chmetcnv>32.5<span lang="EN-US"><span lang="EN-US">℃</span></span><chmetcnv></chmetcnv>,</span>求端差δ<span lang="EN-US">t</span>。<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">δ<span lang="EN-US">t=t'-t1-</span>Δ<span lang="EN-US">t=4.5</span>℃<span lang="EN-US"><p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">66</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、汽机排汽焓<span lang="EN-US"> i1=2260.87kJ/kg</span>,凝结水焓<span lang="EN-US">i=125.6kJ/kg</span>,求蒸气在凝汽器内所放出的热量?<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:解:已知<span lang="EN-US">i1=2260.87kJ/kg<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">i2=125.6kJ/kg<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">q=i2-i1=125.6-2260.87=-2135.27(kJ/kg)<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答:<span lang="EN-US">1</span>千克蒸气在凝汽器内放出<span lang="EN-US">2135.27kJ</span>热量。<span lang="EN-US"><p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">67</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、<span lang="EN-US">10</span>吨水流经过热器后,它的焓从<span lang="EN-US">334.9kJ/kg</span>增加到<span lang="EN-US">502.4kJ/kg</span>,求<span lang="EN-US">10</span>吨水在加热器中吸收多少热量?<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:解:已知<span lang="EN-US">i1=334.9(kJ/kg)<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">i2=502.4(kJ/kg)<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">G=10(t)=1010(kg)<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">q=i2-i1=502.4-334.9=167.5(kJ/kg)<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">Q=Gq=10103167.5=167.5104(kJ)<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答:<span lang="EN-US">10</span>吨水在加热器中吸收<span lang="EN-US">167.5</span>×<span lang="EN-US">104(kJ)</span>的热量。<span lang="EN-US"><p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">68</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、某循环热源温度为<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="527" unitname="℃" wst="on"></chmetcnv><span lang="EN-US">527</span>℃<chmetcnv></chmetcnv>,冷源温度为<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="27" unitname="℃" wst="on"></chmetcnv><span lang="EN-US">27</span>℃<chmetcnv></chmetcnv>,在此温度范围内循环可能达到的最大热效率是多少?<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:解:已知<span lang="EN-US">T1=273+527=800K<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">T2=273+27=300K<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">η最大<span lang="EN-US">=</span>η卡<span lang="EN-US">=1-T2/T1=1-300/800=0.625<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">69</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、某煤的元素分析数据如下:<span lang="EN-US">Cy=60%,Hy=3%,Oy=5%,Ny=1%,Sy=1%,Ay=2%,Wy=10%,</span>求该煤的理论空气量<span lang="EN-US">VK'</span>为多少?<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:<span lang="EN-US">VK'=0.0889[C +0.375(S )]+0.265(H )-0.0333(O )<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">=0.0889(60+0.375</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">×<span lang="EN-US">1)+0.265</span>×<span lang="EN-US">3-0.0333</span>×<span lang="EN-US">5=5.996(</span>牛顿立方米<span lang="EN-US">/</span>千克<span lang="EN-US">)<p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">70</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、为了测定凝汽器内的压力,将一根玻璃管底端插入装有水银的容器中,玻璃管垂直固定,并将玻璃管顶端与凝汽器相接通,若玻璃管中的银上升高度距容器液面<span lang="EN-US">h=<chmetcnv tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="706" unitname="mm" wst="on"></chmetcnv>706mm<chmetcnv></chmetcnv></span>,求凝汽器内的绝对压力及其真空度?(当地大气压<span lang="EN-US">a=9.807</span>×<span lang="EN-US">104Par</span>汞<span lang="EN-US">=13.34</span>×<span lang="EN-US">104N/m2</span>)<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:解:根据流体静力学基本方程,凝汽器的绝对压力<span lang="EN-US"><p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">=Pa-rh=9.807104=13.341040.706=3890(Pa)<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">凝汽器的真空度<span lang="EN-US">v=Pa-P=9.807</span>×<span lang="EN-US">104-3890=94180(Pa)<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">71</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、某风机全风压为<span lang="EN-US">210</span>帕,风量为<span lang="EN-US">100</span>立方米<span lang="EN-US">/</span>秒,轴功率为<span lang="EN-US">30</span>千瓦,试计算该风机效率。<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:解:η<span lang="EN-US">=Qp/N=(210</span>×<span lang="EN-US">100)/30000</span>×<span lang="EN-US">100%=70%<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">72</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、某锅炉炉膛出口过剩空气系数为<span lang="EN-US">1.2</span>,求此处烟气含氧量为多少?<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:解:由α<span lang="EN-US">=21/(21-O2)<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">得:含氧量为<span lang="EN-US">O2=21</span>(α<span lang="EN-US">-1</span>)<span lang="EN-US">/1.2=21</span>(<span lang="EN-US">1.2-1</span>)<span lang="EN-US">/1.2=3.5%<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">73</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、测得某风机入口动压为<span lang="EN-US">10Pa,</span>静压为<span lang="EN-US">-10Pa,</span>出口动压为<span lang="EN-US">30Pa,</span>静压为<span lang="EN-US">200Pa,</span>试计算该风机的全风压。<span lang="EN-US"><br/> <p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:解:根据<span lang="EN-US">H1=H"-H'<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">Hj=200-(-10)=210<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">Hd=Hd"-Hd'<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">Hd=30-10=20<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">H=Hj+Hd <p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">H=210+20=230(Pa)<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答<span lang="EN-US">:</span>该风机的全风压为<span lang="EN-US">230Pa</span>。<span lang="EN-US"><p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">74</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、某炉的额定蒸气量<span lang="EN-US">D=670t/h,</span>锅炉热效率<span lang="EN-US">=92.2%,</span>燃煤量<span lang="EN-US">B=98t/h</span>,煤的低位发热量(<span lang="EN-US">Qd</span>)<span lang="EN-US">y=5000 4.186kJ/kg,</span>制粉系统单耗<span lang="EN-US">nzh=27kWh/t</span>煤,吸风机单耗<span lang="EN-US">nx=2.4kWh/t</span>汽,送风机单耗<span lang="EN-US">nj=3.5kWh/t</span>汽,给水泵单耗<span lang="EN-US">nj=8kWh/t</span>,求该炉的净效率?(标准煤耗<span lang="EN-US">b=350gkWh</span>)<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:解:(<span lang="EN-US">1</span>)锅炉辅机每小时总耗电量为:<span lang="EN-US"><p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">N=D(nx+ns+nj)+B(nzh)=670(2.4+3.5+8)+98.27=9313+2646=11959<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">(2)</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">锅炉的净效率:<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">η<span lang="EN-US">jx=</span>η<span lang="EN-US">r-3600Nb/[B(Qdy)]<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">=92.2%-3600119590.35/(9850004.186)100%=92.2%-7.35%=84.85%<p></p></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答:该炉的净效率为<span lang="EN-US">84.85%</span>。<span lang="EN-US"><p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">75</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">、有一台<span lang="EN-US">E</span>型磨煤机型号为<span lang="EN-US">8.5E,</span>求该磨煤机的最佳转速。<span lang="EN-US"><p></p></span></span></font></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答案:解<span lang="EN-US">:</span>公式<span lang="EN-US"> nz</span>=<span lang="EN-US">115/D1/2r/min<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">式中<span lang="EN-US">nz </span>── 最佳转速<span lang="EN-US">,r/min</span>;<span lang="EN-US"> D </span>── 磨盘直径<span lang="EN-US">,m</span>。<span lang="EN-US"><p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">查出<span lang="EN-US">8.5E</span>型磨煤机<span lang="EN-US">D</span>=<span lang="EN-US">2.16m,</span>代入公式得<span lang="EN-US">:<p></p></span></font></span></p><p></p><p></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">nz</span><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';">==<span lang="EN-US">78.2(r/min)<p></p></span></span></font></p><p></p><p></p><span style="FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-hansi-font-family: 'Times New Roman';"><font size="3">答<span lang="EN-US">:</span>该磨煤机最佳转速为<span lang="EN-US">78.2r/min</span>。</font></span>
[此贴子已经被作者于2006-11-26 10:59:39编辑过] |