廚房排煙風(fēng)量計(jì)算與工廠、實(shí)驗(yàn)室排除有害氣體一樣，要把所有產(chǎn)生的有害氣體全部排除干凈，屬于排煙技術(shù)。那么廚房排煙罩的排煙風(fēng)量計(jì)算內(nèi)容有什么呢？
The calculation of kitchen exhaust air volume is the same as the elimination of harmful gases in factories and laboratories. All the harmful gases produced should be removed clean, which belongs to professional smoke extraction technology. So what is the exhaust air volume calculation content of the kitchen exhaust hood?
煙風(fēng)量計(jì)算，應(yīng)以捕捉產(chǎn)生的全部油煙熱氣為基準(zhǔn)，不是僅等同于簡(jiǎn)單的通風(fēng)換氣。根據(jù)流體力學(xué)原理，對(duì)排煙罩吸排煙氣的流動(dòng)過程加以說明，這樣有助于計(jì)算方法的分析比較，也有助于對(duì)其他類型排煙設(shè)備進(jìn)行計(jì)算分析。
The calculation of smoke air volume should be based on the capture of all the hot gas produced, not just equal to a simple ventilation. According to the principle of fluid mechanics, the flow process of smoke inhalation and exhaust is explained, which is helpful to the analysis and comparison of calculation methods, and also helpful to the calculation and analysis of other types of smoke exhaust equipment.
壓力的傳播，與聲音的傳播是一樣的，在空氣中壓力也是以聲速進(jìn)行傳播。氣體被吸人負(fù)壓區(qū)，形成氣流，以負(fù)壓區(qū)為形成一個(gè)球形的等壓面，也稱作等速面。在這個(gè)等壓面上，壓力大小相等，壓力引起氣流的流動(dòng)速度也相同，流線處處與球形等壓面垂直。
Pressure travels at the speed of sound in the same way that sound does in air. The gas is sucked into the negative pressure area to form a flow, and a spherical isobaric surface is formed at the center of the negative pressure area, also known as the isobaric surface. On this isobaric surface, the pressure is equal, the pressure causes the airflow to flow at the same speed, and the streamline is everywhere perpendicular to the spherical isobaric surface.
在不同半徑的等壓面上，球形面積不同，流速不同，通過球形面積流量相等，也就是與吸風(fēng)口的流量相同。也就是以負(fù)壓區(qū)形成一個(gè)球形的等壓面，流速與到的距離的平方成反比。由于流場(chǎng)為球形空間，所以流速衰減得特別快。
In the isobaric surface with different radius, the spherical area is different and the flow rate is different. The flow through the spherical area is equal, that is, the flow rate is the same as that of the suction outlet. That is, a spherical isobaric surface is formed at the center of the negative pressure zone, and the flow rate is inversely proportional to the square of the distance from the center. Because the flow field is a spherical space, the velocity decays very fast.
由于排煙罩內(nèi)排煙風(fēng)口的負(fù)壓形成以排煙風(fēng)口為的近似球形的等壓面，斗式排煙罩罩口向下，控制壓力傳播方向，球形等壓面是不完整的。排煙罩矩形罩口負(fù)壓形成的等壓面，也可以近似看成以矩形罩口線為圓柱形的等壓面與排煙罩兩端半球形等壓面合成的等壓面。
Because the negative pressure of the exhaust vent in the exhaust hood forms an approximately spherical isobaric surface centered on the exhaust vent, the bucket exhaust hood has a downward cover to control the direction of pressure propagation, and the spherical isobaric surface is incomplete. The isobaric surface formed by negative pressure of rectangular cover of smoke exhaust hood can also be regarded as the isobaric surface synthesized by cylindrical isobaric surface of rectangular cover center line and hemispherical isobaric surface at both ends of smoke exhaust hood.
由于壓力的傳播有繞射能力，
濟(jì)南排煙罩不靠墻的側(cè)面和排煙罩上部的空氣也會(huì)與煙氣相混，進(jìn)人排煙罩。所以，在計(jì)算時(shí)要考慮排煙罩周邊情況，例如，排煙罩四面是靠墻還是敞開，靠墻就減少了等壓面面積，就可以減少空氣的混人，提高排煙的效率。
Because the transmission of pressure has the diffraction ability, the air on the side of the ji 'nan exhaust hood without the wall and the upper part of the exhaust hood will also mix with the smoke and enter the smoke hood. Therefore, the surrounding situation of the exhaust hood should be considered in the calculation. For example, whether the exhaust hood is surrounded by a wall or an open one, the isobaric surface area can be reduced by relying on the wall, the mixing of air can be reduced, and the efficiency of smoke exhaust can be improved.
The exhaust air volume calculation of the kitchen exhaust hood is explained here. If you have any questions about the exhaust hood, please come to the website www.yiruizhoucheng.com for consultation.
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