外文翻譯--自動門滲透速率的預(yù)測（英文）

1、Prediction of infiltration rates through an automatic doorGeorgios H. Vatistas a, Dekang Chen b,*, Tzu-Fang Chen a, Sui Lin aa Department of Mechanical Engineering, Concordia University, Montreal Quebec, Canada b Canarai

2、l Consultants Inc., Montreal Quebec, CanadaReceived 16 November 2005; accepted 5 June 2006 Available online 27 July 2006AbstractAn experimental investigation on infiltration rate through automatic doorways was conducted

3、in an experimental room with three automatic doors. The experimental infiltration rate tested was up to 617 m3/h, which was equivalent to the outdoor air occupying about 47% of the outdoor air supplied to the room. The r

4、esult of the infiltration rate increases with an increase of indoor–outdoor temperature difference. Based on the unbalanced supply-return airflow in a HVAC system, the total infiltration rate was corrected with the combi

5、ned counter and exfiltration airflow and the air lock exchange to develop a reliable correlation. This correlation enables the prediction of the infiltration rate through an automatic door with the cycling of the door op

6、ening and closing. The difference of the calculated result of 580 m3/h of the infiltration rate in comparison with the experimental result of 617 m3/h is about 6% for the indoor and outdoor tem- peratures of 18 ?C and ?1

7、 ?C, respectively. When the outdoor temperature rises from ?1 ?C to 4 ?C, the infiltration rate calculated changes from 580 m3/h to 466 m3/h. ? 2006 Elsevier Ltd. All rights reserved.Keywords: Testing; Modeling; Infiltra

8、tion; Automatic door1. IntroductionAutomatic doors are usually installed in commercial buildings or urban mass transportation, such as buses and light railway vehicles, for customers to pass through the doors. When the d

9、oor opens, significant air infiltrates through the doorway, which represents an extra cooling or heating load. The evaluation of the extra load is very crucial because it can be varied up to 15–20% of the total loading u

10、nder the condition of a large indoor–outdoor temperature difference. Most of the correlations and charts to determine the door infiltration for commercial buildings were obtained from experimental studies, and expressed

11、as a function of the traffic rate indicating persons passing the door per hour [3,4]. The basic consideration used there was that a doorcompleted one cycling of opening and closing when one person passed the door. Howeve

12、r, if many people pass the door simultaneously when the door opens, the above calculation method can not be used directly. The infiltration rate through a doorway is closely related to the indoor–outdoor temperature diff

13、erence, the wind, the door type and size, the door open time and the exfiltra- tion rate etc. The indoor–outdoor temperature difference drives the counter airflow at the doorway due to the air density difference across t

14、he open door. The high density air having a lower temperature flows through the lower part of the door, and the low density air having a higher temperature flows through the top part of the door. There- fore, a neutral l

15、evel must exist at a position of the door height where the air velocity and flow rate are equal to zero. Brown and Solvason [6] studied the heat and mass transfer rates between two rooms with different tempera- tures thr

16、ough different rectangular openings having their dimensions of 600 · 600, 600 · 1200, 900 · 900 and 1200 · 1200. They reasonably assumed that the neutral level located at the midheight of the opening,

17、 and derived an expression from1359-4311/$ - see front matter ? 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.applthermaleng.2006.06.002* Corresponding author. Present address: 5th Floor, No. 100, Hsin Yi Road Se

18、c. 5, Taipei, Taiwan 110. Tel.: +886 2 3725 2504; fax: +886 2 8725 1597. E-mail address: dekangc@gmail.com (D. Chen).www.elsevier.com/locate/apthermengApplied Thermal Engineering 27 (2007) 545–550total outdoor air: 1232

19、m3/h; total return air: 2990 m3/h; total supply air: 4222 m3/h (the sum of the outdoor air and return air).Fourteen thermocouples of 1 m above the floor were used to determine the average temperature Ti in the room (Fig.

20、 1). The total power consumption was measured by a power meter and the average outdoor temperature To was also recorded. The signals from the thermocouples and the power meter were connected to a computer data acquisitio

21、n system. During the test, the average outdoor temperature To maintained at ?1 ?C. The average temperature in the room reached to a stable value Ti when the HVAC unit was run for about four hours. All the doors were clos

22、ed in this stage. Then the three doors operated open/close cycling at the same frequency. The time lengths of an open/close cycling were as follows:opening time: 2.5 s; full open time: 17.5 s; closing time: 2.5 s; full c

23、lose time: 117.5 s.The average temperature in the room would first decrease, and then tend to a stable value Ts, that was lower than the recorded initial average temperature Ti. The input power to the baseboard heaters w

24、as adjusted to increase a value of DW so that the average temperature in the room returned to the initial value Ti. Therefore, the infiltration rate, Qin, could be calculated by following equation:Qin ¼ DWqocpoð

25、;T i ? T sÞ ð1Þ3. Analysis and discussionA significant infiltration rate through the doors was found in the experiment as shown in Fig. 2. The infiltration rate measured was from 512 m3/h to 617 m3/h. The

26、infiltra- tion rate increases almost linearly with the increase of the indoor–outdoor temperature difference DT. An expression given by Kiel and Wilson [1] for the determination of the infiltration rate through a doorway

27、 was:Qin ¼ KWH3 gH Dq? q? ?0:5 ð2Þwhere ? q was the average air density and was defined as:? q ¼ qi þ qo 2 ð3ÞAn experimental correlation for the orifice coefficient K ob- tained by Kie

28、l and Wilson [1] wasK ¼ 0:4 þ 0:0045DT ð4ÞThe calculated infiltration rate Qin obtained from Eqs. (2)– (4) is about 53% higher than the present experimental data as shown in Fig. 2. HVAC systems in so

29、me commercial buildings are unbalanced for the air supply and return as shown in Fig. 3. The amount of conditioned air supplied from a HVAC unit is the sum of the return air and the outdoor air. If the exfiltration throu

30、gh cracks is negligible, the dif- ference between the supply and return airflow rates is equal to the exfiltrates through the doors. The exfiltration rate is up to about 30% of the supply air in some designs, which will

31、affect the infiltration rate through the door. The airflow at a doorway can be considered as an overlap of two flows: the counter airflow and the exfiltration air- flow. Assuming that the neutral lever is at the midheigh

32、t of the door and separates the counter airflow, and that the exfiltration airflow is uniformly distributed on the door surface as shown in Fig. 4a and b, respectively. Fig. 4c illustrates the combined two airflows at th

33、e door- way. The neutral level for the combined airflow moves downward, which results in a reduction of the cross-sec- tional area of the infiltration airflow. From Fig. 4, a cor- relation can be written ashH=2 ¼ V

34、max ? V ex V max ð5ÞBrown and Solvason [6] gave the velocity profile along the height of the doorV ¼ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi2g Dq? q Zsð6ÞFor the maximum infiltration air

35、velocity Vmax at the bot- tom of door, the above Equation becomesV max ¼ffiffiffiffiffiffiffiffiffiffiffiffiffigH Dq? qsð7Þ200300400500600700800900100017 17.5 18 18.5 19 19.5 20Indoor-Outdoor Temperature D

36、ifference, °CInfiltration Rate, m3/hr.Eqs. (14) & (15) Kiel & Wilson (1989) Present ExperimentFig. 2. Infiltration rate through the doors.G.H. Vatistas et al. / Applied Thermal Engineering 27 (2007) 545–550