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Article

Experimental Studies of the Impact of the Geometric Dimensions of the Outlet Opening on the Effectiveness of Positive Pressure Ventilation in a Multi-Storey Building—Flow Characteristics

by
Piotr Kaczmarzyk
1,2,*,
Paweł Janik
1,
Daniel Małozięć
1,
Wojciech Klapsa
1 and
Łukasz Warguła
2
1
Scientific and Research Centre for Fire Protection, National Research Institute, 05-420 Józefów, Poland
2
Faculty of Mechanical Engineering, Institute of Machine Design, Poznań University of Technology, 60-965 Poznań, Poland
*
Author to whom correspondence should be addressed.
Appl. Sci. 2023, 13(9), 5714; https://doi.org/10.3390/app13095714
Submission received: 7 April 2023 / Revised: 26 April 2023 / Accepted: 4 May 2023 / Published: 5 May 2023
Browse Figures
Versions Notes

Abstract

:
During rescue operations, one of the important parameters determining the effectiveness of the implementation of tactical mechanical ventilation is the selection of the appropriate size of the outlet opening. The objective of this article is to determine the effect of the size of the discharge opening area (0.24–1.2 m2) and other factors on the obtained flow parameters (flow velocity, volumetric flow rate and static pressure value) generated by the two tested positive pressure ventilators. The volumetric flow rate was determined by measuring the flow velocity at appropriately selected measurement points. Two ventilator units were tested (one was the conventional type, while two were turbo). During the tests, the fans generated a flow of 4624.17 m3/h to 14,020.92 m3/h (the first—conventional type) and 4884.66 m3/h to 15,656.33 m3/h (the second—turbo type). The analysis carried out in the article can be used as a guideline for designers of buildings, with particular emphasis on cases in which the staircase is not directly adjacent to the façade wall (an escape route built into the axis of the building).

1. Introduction

Positive-pressure ventilators are an important tool used in rescue and firefighting operations. Kaczmarzyk et al. [1] pointed out in 2021 that due to the conditions of use of these devices (operation in a fire environment), they should be characterized by proper efficiency and reliability of operation. Tests related to the use and performance evaluation of mobile fans are being carried out by researchers from around the world. Panindre et al. (2017) performed tests related to the evaluation of the size of the inlet opening on the effectiveness of PPV (positive-pressure ventilation) [2]. During the tests, an increase in the effectiveness of positive pressure ventilation was noted, with the opening area being reduced by installing a smoke curtain. Kaczmarzyk et al. (2022) [3] investigated the effect of the placement distance of a turbo-type fan on the amount of airflow through the exhaust vent. In his tests, he showed that ventilation efficiency (for a turbo unit) increases with increasing positioning distance, but only up to 5 m. In contrast, another research team, which used a conventional fan, showed a relationship in which the closer the fan is positioned, the higher the flow rate is [4]. Kaczmarzyk et al. [5] showed in 2022 that the tested fan achieved the highest output, measured at the surface of the door opening for 4 m (42,269.3 m3/h). The team proved that if a fan is placed at a distance of 1 m the volumetric flow rate will decrease by 38%. With regard to the recommendations being developed on positioning parameters, among other things, it is suggested that some of the research results may already be outdated. This is due to the ongoing development of design elements for fans, in the form of flow direction systems. We are referring to the specially shaped rotor blades and their housing, which is also the flow guide of the generated air stream [6,7]. This evolution is also related to the widespread availability of CFD tools to evaluate the product already at the design stage [8,9]. There are about 60 models of fans on the European market that are used for rescue operations [10]. Half of these units are units powered by an internal combustion engine, and the other half are electric. Fan units have different power ranges. A total of 74% of electric fans are in the 1.1–2.2 kW power range, while fans with combustion engines are in a much larger range from 0.7 to 92 kW. With regard to positive-pressure ventilators, the division of these units into conventional and turbo types is also present in the market [11]. This division is related to the profile and velocity vector of the air stream (i.e., the area of effective distribution versus distance). Analyzing the issues of procedures for assessing the conformity of technical and user parameters, depending on the requirements of the country, these devices may be subject to special requirements [11]. It should also be pointed out that various methods are used in Europe to assess the volumetric flow rate [1,5,12,13]. Nevertheless, as pointed out by Kaczmarzyk et al. in 2022 [11], volumetric airflow tests should be carried out under conditions that reflect real aspects of the operation of this type of equipment—free-flow operation. The use of tactical mechanical ventilation is a very important measure used by fire protection units. The indicated action allows, among other things, the removal of hot and toxic fire gases [14,15], which accumulate in the spaces covered by the fire [16,17]. Over the past years, a number of techniques have been developed to move smoke in building spaces, and these include [18] positive-pressure ventilation, negative-pressure ventilation and positive-pressure attack. Describing the issues that determine the effectiveness of implemented mechanical tactical ventilation during rescue operations, the following parameters should be listed [18]: proper selection of the aeration opening, proper positioning of the fan, ensuring the path of gas pumping is free of obstacles, taking into account atmospheric conditions, and making the right outlet opening (making it of appropriate size). This publication evaluates the effect of the size of the discharge opening on the efficiency of air pumping by a mobile fan. The mentioned parameter is an important aspect that determines the effectiveness of ventilation. According to the recommendations made in the literature [19], it should have appropriate proportions that take into account the dimensions of the inlet opening. According to Cimolino et al. in 2012 [20], if the exhaust opening is too small, the movement of combustion products may be inefficient. On the other hand, setting an outlet opening that is too large may result in an inability to create positive pressure inside the ventilated volume, and in greater susceptibility to the influence of atmospheric conditions (e.g., in the form of wind).
The article evaluates air flow characteristics (air velocity, pressure value and volumetric flow rate) for two types of ventilator units. The flow parameters were measured for each of the five variable outlet sizes, on the surface of a measuring plane fixed in the window. Static pressure values were also recorded simultaneously, at four points—one point on each floor, of a four-story building. The obtained results of the research can provide design guidelines for architects on the selection of roof openings, inside stairwells of residential buildings, which are built into the interior of the building, not adjacent to the façade walls (without access to windows). The performed tests will also allow updates of rescue procedures in fire protection units, in terms of the selection of the size of the discharge opening for the adopted tactical intent in rescue operations. The obtained results, included in Appendix A, can also be used for the validation of numerical models. The most novel aspect of the article is the use of a detailed analysis of the air flow in the outlet opening together with the analysis of the impact of changing its size.

2. Materials and Methods

The tests were conducted using two fans commonly used by firefighting units in Europe [11]. The first fan is a conventional unit, and it is powered by a Briggs & Stratton 750 engine. The maximum power of the engine is 4.4 kW and its displacement capacity is 163 cm3. The manufacturer’s declared volumetric flow rate is 30,000 m3/h. The second fan is a turbo unit and is powered by a Honda GX200 internal combustion engine with the maximum power of the engine being 4.1 kW. The displacement of the spark-ignition internal combustion engine of this device is 196 cm3. For the turbo fan, the manufacturer indicated that it generates of 31,799 m3/h of flow rate. The tests on flow characteristics, for the indicated samples, were carried out on a 7-story building, from which 4 floors were selected for testing. For these 4 floors, the volume of the gas exchange track was 198 m3. A test stand (FRC—flow resisting curtain) was installed on the 4th floor inside a window opening (present in the southeast wall), allowing the measurement of airflow velocity profiles generated by mobile fans, with the possibility of changing the size of the measurement area. The specified test stand was designed and manufactured by Centrum Naukowo-Badawcze Ochrony Przeciwpożarowej—Państwowy Instytut Badawczy (Scientific and Research Center for Fire Protection—National Research Institute). The stand is constructed of a metal body (frame), which is tightly fitted to the window frame. The device is equipped with a roller shutter made of plastic, which, depending on the setting, changes the area of the outlet opening. On the front part of the measuring plane, guides made of aluminium profiles are fixed, which are used to transport the measuring module. A thermo-resistive anemometer is embedded in this module, which moves in a synchronized manner taking into account the current size of the outlet opening (position of the shutter). The station is driven by a stepper motor and its control (the position of the roller shutter and the sensor transport path) is possible due to a computer application that works with a dedicated controller.
The tests of flow characteristics—volumetric flow rate—were performed by measuring the air flow velocity at the surface of the outlet hole, the measuring plane. The measurement was carried out, based on the requirements of the ISO 5221 standard [21]. The evaluation of flow velocity was carried out for 5 positions of variable outlet area: P1 (0.24 m2); P2 (0.48 m2); P3 (0.72 m2); P4 (0.96 m2); P5 (1.2 m2). A diagram of the test stand, including the distribution of measurement points, is shown in Figure 1. Air jet velocity was measured using a measurement module, which was equipped with a TSI 8455 thermo-resistive anemometer (0.127–50 m/s and 1% accuracy). The volumetric air flow rate was calculated taking into account the dependence of the product (ratio) on the average flow velocities and the geometric surface of the outlet opening [8]. At the same time, along with flow velocity measurements, pressure values were recorded (using Setra 265 transducers with a measurement range of 0–100 Pa and an accuracy of 0.25%). For the implementation of the research, 4 transducers were used, 1 being distributed on each floor, and fixed inside the building in the center of the front wall (Figure 1.). This selection of the measurement point was intended to measure the pressure as closely as possible to the average static pressure on a given floor—an area away from places where air movement can produce local back pressure or negative pressure.
During the tests, the fans were set up in the following configuration—fan 1 (conventional) was positioned at a distance of 1 m, and the impeller angle was 17°. Meanwhile, the positioning distance for fan 2 was 5 m, and the angle of inclination was 6°. The indicated positioning parameters represented the most effective positioning of both units (in which the highest volumetric flow rate was recorded), as determined in earlier tests [5]. During the tests, the fans operated at the maximum rotational speed of the drive units, and this speed also corresponded to the highest capacity of the volumetric air flow rate. The frequency of acquisition of air jet velocity parameters and pressure values was 10 Hz, and the measurement itself lasted 30 s at each velocity sounding point. With regard to the analysis of the measurement error, the arithmetic mean was taken as the estimator of the desired value, and the standard deviation of the arithmetic mean was taken as the indicator of measurement uncertainty. Meanwhile, the results of the main test provided mean airflow rates from 24, 48, 72, 96 and 120 trials (N = 24, 48, 72, 96 and 120), for which confidence intervals were determined at the 95% confidence level (p = 0.05). Significant statistical differences were analyzed using Student’s T-test. The tests were performed between August and September. During the tests, environmental conditions were monitored. The tests were performed at a temperature of 21 ± 5 °C and humidity of 50 ± 10%. The tests were carried out on days when wind speed was ≤0.2 m/s. Wind measurements were taken near the discharge opening (measurement plane).

3. Results and Discussion

The results of the air jet velocity profiles measured on the surface of the outlet hole are shown in Figure 2 for fan 1 and Figure 3 for fan 2. Due to the considerable amount of measurement data, information related to measurement accuracy has not been marked on the trifunctional charts. This information is included as an Appendix A (Table A1 and Table A2), in which the results of the average velocities, for each measurement point, are shown separately for each opening area of the FRC flow damper (P1–P5). In Table A3 and Table A4, a summary of the average pressures recorded on each floor (I–IV) for all five throttle opening surfaces (P1–P5) is presented. On the other hand, Table A5 shows the volumetric flow rate that was pumped through the object, for five areas of the measurement plane opening, for both fan units. Analyzing the characteristics of air flow velocity in the outlet (Figure 2 and Figure 3), it can be observed that as the size of the outlet increases, the highest flow velocity is concentrated in the lower and upper parts of the outlet. The flow velocity values coincide with the results of Łapicz et al. in 2018, who reported average flow velocities in the outlets ranging from 2 m/s to 7.6 m/s [22]. The highest flow velocity was obtained for a hole with a shape similar to that of a full bore outlet [22]. Additionally, studies by Kuti et al. in 2018 and Lambert and Merci in 2013 characterized flow velocities in the outlet in similar ranges, from 1 m/s to 3 m/s [4,23].
The effect of the size of the outlet cross-section on the flow parameters—volumetric flow rate and static pressure value—is shown in Figure 4. The presented flow characteristics were made on the basis of the data in Table A1, Table A2, Table A3, Table A4 and Table A5.
Analyzing the obtained results of the flow parameters (volumetric flow rate as a function of pressure), it is indicated that both fans obtained the highest values of volumetric flow rate, for the largest area of the outlet opening—P5 (1.2 m2). Under these conditions, fan 1 pumped 14,020.92 ± 702.19 m3/h, while fan 2 pumped 15,656.33 ± 838.66 m3/h. The smallest volumetric flow rate was recorded for the smallest measurement plane opening area (P1—0.24 m2), where fan 1 pumped 4624.17 ± 116.70 m3/h and fan 2 pumped 4884.66 ± 190.20 m3/h. Analyzing the pressure parameter, it should be pointed out that the largest values were obtained for the smallest opening areas of the P1 damper (0.24 m2). Fan 1 generated pressures of 39.7 Pa, while fan 2 generated pressures of 27.9 Pa. A limitation of the inference from the conducted analyses is the influence of the temperature inside the building during rescue fire operations [24,25,26].
As presented in Figure 4, both cases differed substantially in terms of their characteristics (which are generated in the building pressure in relation to the flow rate). The differences were highest in low restrictor areas when the ventilator jet encountered the highest backpressures. It should be noted that for both cases, a five-fold increase in outlet surface area resulted in only a three-fold increase in the volume flow rate. It can also be noted that especially for high flowrates (a high outlet area), most of the pressure drop occurs on the way through the staircase. on the relation between a fraction of the pressure drop occurring in the controlled outlet area restrictor and the pressure drop along the whole flowpath is shown in Figure 5. For this parameter, both cases had almost identical behavior despite having different characteristics, as shown on Figure 4. This observation suggests that the relation of pressure drops along the flowpath is independent of the ventilator type and position, and is rather a function of the geometric configuration of the building (this is in accordance with the incompressible internal flow theory) [27]. Another observation is the fact that for a given configuration, when the outlet area is above 1 m2, the flow resistance contribution of the outlet restriction is below 50%. The last curve shown in Figure 5 is the φ , given by Equation (1):
φ = 1 A r 2 1 A r 2 + ∑ 1 C d · A c 2
where
  • – Ar—area of outlet restrictor,
  • – Ac—areas of consecutive restrictions along the flowpath—here taken as three consecutive openings between staircase storeys with 2.4 m2 each,
  • – Cd—relative discharge coefficient, a dimensionless parameter describing how much less effective is the restriction area Aç compared to the outlet restrictor because of secondary losses in the building.
The difference between φ values from the experiment and the one from Equation (1) indicates the contribution of secondary pressure losses due to wall friction, stair interaction, and flow direction changes along the flowpath. The proximity of the experimental results to Equation (1) suggests, however, that the flowpath area constrictions were the main sources of the building flow resistance. The practical conclusion to be taken from these observations is that after the outlet area becomes close to the area of flow restrictions along the flowpath inside the building, it is more important to decrease flowpath resistance by limiting pressure drop due to area constrictions in the building or to increase the pressure induced by ventilators, than it is to further increase the outlet surface area.

4. Conclusions

Buildings being currently constructed are characterized by increasingly complex room layouts and the presence of unusual interior finish materials, which means that providing an effective fire ventilation system can be extremely difficult. A special case worth noting is that of vertical escape routes (stairwells) built centrally inside the building, with no access to the external façade wall, and therefore no openings in the form of windows to provide gravity supply and exhaust.
  • The analysis performed in the article can provide design guidelines for architects on the selection of roof openings, inside stairwells of residential buildings, which are built into the interior of the building, not adjacent to the façade walls (without access to windows). Moreover, the performed research may allow updates to be made to the rescue procedures in fire protection units, in terms of the selection of the size of the discharge opening for the adopted tactical rescue intention.
  • The performed tests confirmed that the change in the area of the outlet opening inside the ventilated volume is an important parameter determining the effectiveness of the implemented ventilation. Depending on the fire conditions in the facility and the tactical rescue intention of the commander of the operation, the level of opening of the outlet opening should be adjusted. If it is necessary to provide evacuation conditions in the escape route (for example, in a multi-story facility) and if the products of thermal decomposition disperse inside such a facility, then it will be desirable to make the outlet opening as large as possible.
On the other hand, when there is a need to secure an escape route during rescue operations, it will be more beneficial to make an opening with a smaller area. Such action will allow the creation of positive pressure inside the ventilated volume. In addition, the analysis noted that the ratio of pressure drops along the flowpath is independent of the position of the fan; it depends on the geometric configuration of the building. The observed decrease in the proportion of flow resistance at the outlet with an increasing outlet cross-section (increasing in the tested range by about 58%) suggests that enlarging the outlet field beyond the area of the constrictions present inside the building does not significantly increase the efficiency of ventilation. The factor that then determines to a greater extent the size of the pumped flow is the provision of an obstacle-free gas exchange path in the ventilated volume. This action will reduce the resistance of the flowpath by reducing pressure drops (caused by obstacles and constrictions) and increase the flow induced from the environment by mobile fans.

Author Contributions

Conceptualization, P.K., P.J., D.M. and W.K.; methodology, P.K., P.J., D.M. and Ł.W.; software, P.K. and P.J.; validation, P.K., P.J., D.M. and W.K.; formal analysis, P.K., P.J., D.M., W.K. and Ł.W.; investigation, P.K., P.J., D.M. and W.K.; resources, P.K., P.J., D.M., W.K. and Ł.W. data curation, P.K., P.J., D.M., W.K. and Ł.W.; writing—original draft preparation, P.K., Ł.W., P.J. and D.M.; writing—review and editing, P.K. and Ł.W.; visualization, P.K.; supervision, P.J. and D.M.; project administration, P.J., D.M. and PK.; funding acquisition, P.K., P.J., D.M. and W.K. All authors have read and agreed to the published version of the manuscript.

Funding

The research presented in the article was carried out as part of the Ministry of Education and Science program’s “Implementation Doctorate” executed in 2020–2024 (agreement no. DWD/4/22/2020).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

Appendix A

Table
Table A1. Air flow velocity (for 5 different areas of the window opening)—fan 1, where: x—position of the measurement point with respect to the x-axis, y—position of the post-measurement point with respect to the y-axis, AVG—arithmetic mean of the flow rate, SD—standard deviation taken as measurement error.
Table A1. Air flow velocity (for 5 different areas of the window opening)—fan 1, where: x—position of the measurement point with respect to the x-axis, y—position of the post-measurement point with respect to the y-axis, AVG—arithmetic mean of the flow rate, SD—standard deviation taken as measurement error.
Distance of the Fan from the Door Opening: 1 m
The Inclination Angle of the Fan Impeller Relative to the Ground: 17°
Stage P1/5x (mm)
50150250350450550650750
AVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSD
y (mm)504.890.195.580.116.070.086.100.146.090.095.260.165.500.215.470.16
1505.390.065.330.095.120.075.070.125.010.114.800.114.670.164.520.11
2505.160.035.400.115.530.196.070.126.060.125.930.154.840.444.600.13
Stage P2/5x (mm)
50150250350450550650750
AVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSD
y (mm)505.490.105.680.115.950.125.940.105.910.236.040.126.230.145.900.06
1504.800.124.710.094.970.084.610.154.470.144.390.094.390.184.820.14
2504.760.124.960.124.850.104.550.104.250.134.640.074.310.134.090.24
3505.020.114.910.065.010.094.780.064.690.114.740.174.090.183.850.18
4504.790.094.950.125.110.145.440.195.410.105.010.054.640.134.060.21
5504.690.074.280.174.700.114.890.134.910.254.270.773.580.463.500.19
Stage P3/5x (mm)
50150250350450550650750
AVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSD
y (mm)505.010.125.350.075.090.115.270.105.650.075.730.175.250.165.130.14
1504.410.064.620.074.690.074.530.144.320.114.390.144.650.133.930.21
2504.220.114.520.074.320.074.170.084.130.103.950.114.210.083.710.23
3504.190.154.310.084.410.134.130.184.100.103.870.163.710.123.230.41
4504.260.114.330.104.410.154.040.184.130.124.150.183.770.123.340.48
5504.060.184.570.144.770.214.940.344.560.144.510.133.760.153.730.07
6504.320.074.560.064.790.194.890.174.780.154.450.144.030.123.750.18
7504.460.234.370.094.540.134.470.144.380.184.400.203.870.213.470.21
8503.990.074.130.084.100.114.120.143.970.293.290.502.810.612.990.47
Stage P4/5x (mm)
50150250350450550650750
AVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSD
y (mm)504.540.064.900.084.690.144.520.304.700.154.950.134.920.324.950.06
1503.760.124.330.04.270.094.160.124.230.134.220.164.430.063.760.11
2503.530.224.120.043.900.073.860.073.820.133.920.133.800.193.150.16
3503.160.233.840.083.860.123.600.133.500.063.500.163.440.092.470.19
4503.540.093.860.113.720.113.240.133.560.073.550.103.360.132.410.40
5503.210.283.910.173.890.103.580.093.430.113.480.203.160.142.430.45
6503.440.144.100.124.030.134.100.193.940.203.760.093.580.132.910.33
7503.160.233.750.084.190.264.500.234.060.173.790.113.420.142.910.13
8503.160.363.890.094.170.074.700.244.040.143.930.153.530.143.260.21
9503.200.214.130.123.930.174.050.164.210.213.870.093.530.133.280.15
10503.440.263.910.073.600.103.640.133.520.133.010.253.130.353.260.26
11503.810.163.520.093.440.133.510.242.980.313.140.112.910.462.620.52
Stage P5/5x (mm)
50150250350450550650750
AVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSD
y (mm)504.100.134.290.183.920.303.750.323.360.293.410.514.120.404.290.18
1502.680.183.550.073.690.103.930.083.800.093.990.093.900.123.190.19
2503.020.263.640.083.610.053.610.103.530.063.710.173.830.132.970.37
3502.680.223.520.063.430.103.340.123.240.123.230.153.460.082.850.19
4502.930.313.400.083.330.143.150.083.200.123.150.083.260.132.480.24
5502.600.283.040.163.210.063.100.103.090.083.290.143.340.122.310.14
6502.820.313.410.103.370.123.290.133.290.113.170.063.100.131.940.13
7502.870.173.560.093.460.093.360.163.240.093.150.142.930.052.420.11
8502.450.343.440.103.490.143.450.193.740.173.450.043.060.292.590.15
9502.100.373.400.133.690.123.940.263.760.323.650.122.960.142.650.13
10501.970.303.450.113.460.053.820.143.770.193.680.143.300.112.770.20
11501.590.143.240.163.640.093.150.173.240.133.330.162.840.162.870.12
12501.930.313.250.163.210.163.300.143.400.083.330.122.770.182.470.21
13502.390.233.500.093.750.133.750.073.330.083.490.173.060.102.670.14
14503.060.243.730.113.430.103.220.283.310.553.560.182.960.272.760.25
Table
Table A2. Airflow velocity (for 5 different areas of the window opening) for fan 2, where x is the position of the measurement point with respect to the x-axis, y is the position of the measurement point with respect to the y-axis, AVG is the arithmetic mean of the flow intensity, and SD is the standard deviation taken as measurement error.
Table A2. Airflow velocity (for 5 different areas of the window opening) for fan 2, where x is the position of the measurement point with respect to the x-axis, y is the position of the measurement point with respect to the y-axis, AVG is the arithmetic mean of the flow intensity, and SD is the standard deviation taken as measurement error.
Distance of the Fan from the Door Opening: 5 m
The Inclination Angle of the Fan Impeller Relative to the Ground: 6°
Stage P1/5x (mm)
50150250350450550650750
AVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSD
y (mm)506.320.206.810.126.290.156.580.246.230.186.180.175.960.146.220.14
1505.720.105.780.105.560.175.620.135.350.105.040.235.100.144.850.18
2505.270.144.200.785.740.244.850.635.680.135.710.305.700.424.960.14
Stage P2/5x (mm)
50150250350450550650750
AVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSD
y (mm)506.310.096.220.126.490.236.650.146.710.166.590.176.440.695.300.59
1504.480.693.710.264.620.154.820.434.950.234.920.115.250.115.170.18
2505.240.144.410.685.240.144.310.404.340.565.010.134.960.314.520.09
3504.800.285.290.195.580.205.160.135.120.205.310.084.730.174.340.14
4505.280.095.270.105.680.185.960.136.040.135.400.145.020.114.310.30
5504.490.185.170.105.410.145.760.145.370.405.000.233.060.283.840.29
Stage P3/5x (mm)
50150250350450550650750
AVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSD
y (mm)505.780.106.140.175.770.186.000.236.330.226.510.106.560.105.910.12
1504.960.115.330.075.200.154.960.224.530.295.310.215.160.214.610.15
2504.760.134.490.304.630.104.520.164.540.174.270.134.370.074.550.13
3504.530.304.790.174.540.324.640.094.520.074.340.164.080.143.670.27
4504.570.264.190.344.670.424.030.124.280.834.680.113.990.253.850.34
5504.700.184.910.205.300.234.950.104.990.204.360.173.790.313.380.74
6504.820.175.160.105.160.155.500.205.140.104.830.154.470.084.140.14
7503.880.654.950.184.850.183.950.575.130.185.030.114.510.424.120.23
8504.130.374.270.224.930.164.550.194.390.353.660.392.600.612.450.51
Stage P4/5x (mm)
50150250350450550650750
AVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSD
y (mm)505.390.085.420.105.630.225.500.145.300.255.740.215.860.205.620.26
1504.260.244.740.094.870.104.640.154.810.074.860.084.740.184.100.20
2504.110.154.550.054.340.074.220.094.350.154.270.184.380.193.960.20
3503.970.204.390.084.240.073.930.094.010.114.080.204.180.292.990.26
4504.140.104.250.094.060.123.960.093.890.103.810.133.670.153.360.18
5503.880.254.440.114.350.154.120.124.080.093.920.093.440.183.010.29
6503.880.314.350.104.400.124.740.224.310.114.330.113.600.203.190.26
7503.670.244.560.054.730.164.730.225.100.284.360.144.020.143.590.17
8503.390.234.540.164.570.104.790.184.950.314.410.204.090.123.330.17
9503.480.334.550.084.420.124.630.224.500.304.470.104.050.103.020.38
10503.770.194.430.154.230.094.470.114.360.174.190.163.510.363.420.23
11504.040.083.870.143.930.103.900.213.700.282.690.662.150.722.870.25
Stage P5/5x (mm)
50150250350450550650750
AVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSDAVGSD
y (mm)504.400.074.200.124.220.174.250.284.090.074.130.244.360.284.580.22
1503.700.184.200.054.400.144.230.064.510.124.360.194.370.124.630.14
2503.380.324.060.074.080.103.950.074.090.094.100.184.320.193.050.26
3502.950.433.910.113.790.083.810.163.780.143.920.173.920.082.680.35
4502.310.543.090.133.200.153.550.083.500.103.300.243.210.262.370.20
5502.290.633.650.123.420.083.360.133.540.103.270.133.050.262.400.26
6503.470.213.780.093.830.133.590.063.630.133.310.113.240.172.520.26
7503.130.243.830.083.790.184.280.343.610.103.470.093.240.172.430.24
8502.480.643.500.314.000.264.090.253.850.093.870.163.480.232.880.16
9502.810.194.040.104.220.114.220.374.320.144.090.163.180.232.390.25
10502.590.334.310.224.300.134.220.164.330.204.080.13.530.213.220.13
11502.620.274.290.094.150.164.000.214.160.164.390.153.530.253.260.20
12502.410.333.850.173.930.123.870.123.910.123.690.122.380.393.470.18
13502.380.193.880.093.850.103.790.183.400.203.410.573.040.303.110.45
14502.980.113.720.183.980.113.910.203.940.323.540.363.660.363.350.11
Table
Table A3. Effect of the size of the area of the aperture opening (5 variable areas of the outlet opening) on the value of static pressure (Pa) on floor I-IV inside the staircase)—fan 1, where AVG—arithmetic mean of the flow rate, SD—standard deviation taken as measurement error.
Table A3. Effect of the size of the area of the aperture opening (5 variable areas of the outlet opening) on the value of static pressure (Pa) on floor I-IV inside the staircase)—fan 1, where AVG—arithmetic mean of the flow rate, SD—standard deviation taken as measurement error.
Ventilator 1
Stage
(Opening Level)		StoreyAverage (Pa)
IIIIIIIV
AVGSDAVGSDAVGSDAVGSD
P1/539.723,0239.442.9938.742.9437.812.8438.93
P2/535.322.4634.132.2931.752.1329.121.9532.58
P3/531.942.1229.641.9525.511.7521.061.5727.04
P4/529.871.9326.51.6120.581.3714.561.0722.88
P5/528.152.2824.151.8117.531.6510.781.6320.15
Table
Table A4. Effect of the size of the aperture area (5 variable areas of the outlet opening) on the value of static pressure on floor I-IV inside the staircase) for fan 2, where AVG is the arithmetic mean of the flow rate, and SD is the standard deviation taken as measurement error.
Table A4. Effect of the size of the aperture area (5 variable areas of the outlet opening) on the value of static pressure on floor I-IV inside the staircase) for fan 2, where AVG is the arithmetic mean of the flow rate, and SD is the standard deviation taken as measurement error.
Ventilator 2
Stage
(Opening Level)		StoryAverage [Pa]
IIIIIIIV
AVGSDAVGSDAVGSDAVGSD
P1/528.813.8728.183.7727.683.6727.093.5227.94
P2/526.833.4125.593.2223.722.9421.672.6224.45
P3/525.882.8123.692.5620.372.2316.831.8821.69
P4/525.293.0522.252.6917.532.2312.641.819.43
P5/522.812.3919.242.1114.281.929.191.9816.38
Table
Table A5. Effect of the size of the aperture area (5 variable areas of the outlet aperture) on the airflow rate for fans 1 and 2, where AVG is the arithmetic mean flow rate (m3/h) and confidence interval (p = 0.05).
Table A5. Effect of the size of the aperture area (5 variable areas of the outlet aperture) on the airflow rate for fans 1 and 2, where AVG is the arithmetic mean flow rate (m3/h) and confidence interval (p = 0.05).
Volumetric Airflow Rate [m3/h]
Stage
(Opening Level)		Ventilator 1Ventilator 2
AVGSDAVGSD
P1/54624.17116.704884.66190.20
P2/58352.17257.778929.08411.81
P3/511,142.00418.4812,149.28596.15
P4/512,854.76566.2114,548.14611.63
P5/514,020.92702.1915,656.33838.66

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Applsci 13 05714 g001 550
Figure 1. Configuration of the test system: 1—the fan, 2—the window opening (measuring plane with the division of rest of the measuring points, (from the left) P1–24, P2–48, P3–72, P4–96 and P5–120), 3—the measuring probe (TSI thermo anemometer), 4—the body of the test stand and the shutter modifying the size of the outlet opening, and 5—the guides for transporting the measuring probe.
Figure 1. Configuration of the test system: 1—the fan, 2—the window opening (measuring plane with the division of rest of the measuring points, (from the left) P1–24, P2–48, P3–72, P4–96 and P5–120), 3—the measuring probe (TSI thermo anemometer), 4—the body of the test stand and the shutter modifying the size of the outlet opening, and 5—the guides for transporting the measuring probe.
Applsci 13 05714 g001
Applsci 13 05714 g002 550
Figure 2. Airflow velocity in the outlet opening for fan 1, positioned at a distance of 1 m from the door opening, with an angle of inclination of 17° and an area of the outlet opening at (a) P1, (b) P2, (c) P3, (d) P4, and (e) P5.
Figure 2. Airflow velocity in the outlet opening for fan 1, positioned at a distance of 1 m from the door opening, with an angle of inclination of 17° and an area of the outlet opening at (a) P1, (b) P2, (c) P3, (d) P4, and (e) P5.
Applsci 13 05714 g002
Applsci 13 05714 g003 550
Figure 3. Airflow velocity in the outlet for fan 2, set at a distance of 5 m from the door opening, with an angle of inclination of 6° and an area of the outlet opening of at (a) P1, (b) P2, (c) P3, (d) P4, and (e) P5.
Figure 3. Airflow velocity in the outlet for fan 2, set at a distance of 5 m from the door opening, with an angle of inclination of 6° and an area of the outlet opening of at (a) P1, (b) P2, (c) P3, (d) P4, and (e) P5.
Applsci 13 05714 g003
Applsci 13 05714 g004 550
Figure 4. Flow characteristics (as a function of air flow from average pressure values) of 2 types of positive pressure ventilators for 5 different surface opening positions (P1–P5).
Figure 4. Flow characteristics (as a function of air flow from average pressure values) of 2 types of positive pressure ventilators for 5 different surface opening positions (P1–P5).
Applsci 13 05714 g004
Applsci 13 05714 g005 550
Figure 5. Outlet restrictor pressure drop as a fraction of the whole flowpath pressure drop; Equation (1) is for Cd 0.7.
Figure 5. Outlet restrictor pressure drop as a fraction of the whole flowpath pressure drop; Equation (1) is for Cd 0.7.
Applsci 13 05714 g005
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MDPI and ACS Style

Kaczmarzyk, P.; Janik, P.; Małozięć, D.; Klapsa, W.; Warguła, Ł. Experimental Studies of the Impact of the Geometric Dimensions of the Outlet Opening on the Effectiveness of Positive Pressure Ventilation in a Multi-Storey Building—Flow Characteristics. Appl. Sci. 2023, 13, 5714. https://doi.org/10.3390/app13095714

AMA Style

Kaczmarzyk P, Janik P, Małozięć D, Klapsa W, Warguła Ł. Experimental Studies of the Impact of the Geometric Dimensions of the Outlet Opening on the Effectiveness of Positive Pressure Ventilation in a Multi-Storey Building—Flow Characteristics. Applied Sciences. 2023; 13(9):5714. https://doi.org/10.3390/app13095714

Chicago/Turabian Style

Kaczmarzyk, Piotr, Paweł Janik, Daniel Małozięć, Wojciech Klapsa, and Łukasz Warguła. 2023. "Experimental Studies of the Impact of the Geometric Dimensions of the Outlet Opening on the Effectiveness of Positive Pressure Ventilation in a Multi-Storey Building—Flow Characteristics" Applied Sciences 13, no. 9: 5714. https://doi.org/10.3390/app13095714

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