Visualization of hot flows of tall space fires in model experiments with Schlieren Photography technique

Su, ChungHwei; Wang, ShiuanCheng; Shih, ChiaYuan; Yang, YungChang

doi:10.1186/s40064-016-3422-8

Cited by 4 publications

(4 citation statements)

References 33 publications

(34 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A previous study proved that the Schlieren image is very similar to the simulated image if the FDS simulation result shows the maximum temperature is 45°C (Su et al , 2016).…”

Section: Experimental Equipment and Numerical Simulation Conditionsmentioning

confidence: 64%

“…Compared with the temperature and smoke distribution in the full-scale space building simulated by FDS, the experimental image at 120 s and the simulated image at 425 s show that the two hot gases are consistent (Su et al , 2016), as shown in Figure 6(a). It is observed that the outside air flows in the lower left inlet, so that the internal hot gas is blown to the right wall.…”

Section: Resultsmentioning

confidence: 95%

See 1 more Smart Citation

Analysis of makeup air in a natural smoke vent system in a tall space using numerical simulation and Schlieren technique

Shih

Chen

Su³

et al. 2019

HFF

Self Cite

View full text Add to dashboard Cite

Purpose The purpose of this paper is to analyze the phenomenon of makeup effect using numerical simulation and model experiments on seven different natural smoke extraction patterns of tall space. Airflow distribution and heat accumulation phenomenon in different cases are compared. The natural smoke exhaust system for tall spaces has many advantages, including low cost, no power and low maintenance cost. It is more advantageous than the mechanical type of exhaust. However, the internal air distribution is complicated since the large span spatial character. Effective and correct verification method is very important for the analysis of flow fields in tall spaces. Design/methodology/approach This study used fire dynamics simulator (FDS) software to simulate the fire scene. The model experiments are conducted to determine if the numerical simulation results are reasonable. A single-mirror Schlieren system, including an 838 (H) × 736 mm (W) square concave mirror, as well as the focal length of 3,100 mm was adopted to record the dynamic flow of hot gas. Six smokeless candles were burned in a 1/12.5 model in experiments to record the distribution of inflow, accumulation and outflow of airflow in the space. In addition, the thermocouple lines were mounted in the model for temperature measurement. Findings The results of numerical simulation and model experiments have proved that makeup air has a significant effect on the effectiveness of a natural smoke vent system. Larger areas of smoke vents will produce more heat accumulation phenomenon. In this study, the air inlet and vent installed on the same side have a better heat removal effect. Moreover, Schlieren photography technique is proved to be an accurate measurement method to record the dynamic flow of hot air immediately, directly and accurately. The dynamic flow behavior of hot gas in the model has been visualized in this paper. Originality/value At present, there is no examination method other than checking the smoke vent area to validate the effectiveness of a natural smoke vent system in Taiwan, as well as no requirements regarding the makeup inlet. The effect of makeup air in generating the effective push-pull phenomenon of airflow has been analyzed. In addition, the post-combustion hot gas distributions were visualized by using Schlieren photography technology in the model space, compared with the FDS simulation result and thermocouple recorded temperature. A verification method in the model experiments is established to determine if the numerical simulation results are reasonable.

show abstract

“…A previous study proved that the Schlieren image is very similar to the simulated image if the FDS simulation result shows the maximum temperature is 45°C (Su et al , 2016).…”

Section: Experimental Equipment and Numerical Simulation Conditionsmentioning

confidence: 64%

Section: Resultsmentioning

confidence: 95%

Analysis of makeup air in a natural smoke vent system in a tall space using numerical simulation and Schlieren technique

Shih

Chen

Su³

et al. 2019

HFF

Self Cite

View full text Add to dashboard Cite

show abstract

“…A previous study proved that if the maximum temperature of the color scale in the FDS simulation is set to 45°C, the Schlieren image will be similar to the numerical simulation. (Su et al , 2016). As the scale was 1/12.5, the recording time of the simulation result was 12.5 times the experimental result.…”

Section: Parameters Of Numerical Simulations and Experimental Modelsmentioning

confidence: 99%

Analysis of tilted neutral planes for tall space fires with unsymmetrical openings using numerical simulation and Schlieren photography technique

Su¹,

Wang²

2019

HFF

Self Cite

View full text Add to dashboard Cite

Purpose The purpose of this paper is to analyze the variations in the neutral plane when a tall space with unsymmetrical openings is on fire. The neutral plane of the fire scene is an important index of a natural smoke exhaust system. The numerical simulation method and the Schlieren photography technique were used as analysis tools. The results of model experiments and numerical simulation were compared with each other to confirm the rationality of the conclusions. The results were to discuss the characteristics of various cases and showed that the neutral planes of the fire scene were not always horizontal. Design/methodology/approach The numerical simulation method and the Schlieren photography technique were used as analysis tools. The flow patterns of hot air in various cases were recorded using the flow visualization technique. In addition, the renowned simulation software, fire dynamics simulator (FDS), was used for case analysis. The Schlieren photography technique was used for 1/12.5 model experiments with six smokeless candles burned, and FDS was used for a numerical simulation. In terms of the case of unilateral vents, the exhaust efficiency was discussed when the exhaust vent and air inlet were located on the same side or different sides. Findings This study demonstrates that makeup air flowing in from the inlets and openings has a significant impact on the effectiveness of natural smoke exhaust systems. The results illustrated that the neutral planes were tilted in some cases. In some cases, the results showed that one side was the air inlet and the other side was the exhaust vent, even if the openings were at the same height in some cases. These phenomena have rarely been discovered or studied in the past. The exhaust efficiency was not always better when the vent was located in the rooftop. Originality/value This study analyzed the neutral plane of a fire scene using the common unsymmetrical opening spaces in the Taiwan region as an example. The phenomenon of non-horizontal neutral plane has rarely been studied in the past. The temperature of the discharged hot gas was low because of an efficient exhaust effect, which reduced the heat and smoke storage in the space. The results obtained by these two methods were consistent, and showed that the cases with the same opening area had different smoke extraction efficiencies, meaning the smoke extraction effect cannot be judged only by the opening areas.

show abstract

“…This method is extremely useful for the visualization and evaluation of high-speed phenomena, mainly in the engineering field. 8,9 The following experiments were conducted with the intra-gastric pressure of an excised swine stomach maintained at 8 mmHg using a carbon dioxide insufflation system (GW-200; Fujifilm, Tokyo, Japan). A thin endoscope (EG-6400N; Fujifilm) was advanced into the stomach, and gas leakage from the biopsy valve during insertion and withdrawal of the biopsy forceps was visualized (Fig.…”

mentioning

confidence: 99%

Is simply covering the patient's mouth with a surgical mask during transnasal endoscopy sufficient as an anti-COVID-19 measure?

et al. 2023

View full text Add to dashboard Cite

Visualization of hot flows of tall space fires in model experiments with Schlieren Photography technique

Cited by 4 publications

References 33 publications

Analysis of makeup air in a natural smoke vent system in a tall space using numerical simulation and Schlieren technique

Analysis of makeup air in a natural smoke vent system in a tall space using numerical simulation and Schlieren technique

Analysis of tilted neutral planes for tall space fires with unsymmetrical openings using numerical simulation and Schlieren photography technique

Is simply covering the patient's mouth with a surgical mask during transnasal endoscopy sufficient as an anti-COVID-19 measure?

Contact Info

Product

Resources

About