• Journal of Biosystems Engineering
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• 제34권1호
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• pp.63-68
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• 2009

This study was carried out to determine necessary conditions for optimal ventilation of small windowless piglet house (5.2 (W) ${\times}$ 12.3 (L) ${\times}$ 2.3 (H) m) with negative tunnel ventilating system using CFD (Computational Fluid Dynamics) simulation. The weaning piglet house for this experiment was consisted of 4 rooms (520 (W) ${\times}$ 300 (L) cm), 3 fences (70 (H) cm), 1 air inlet (350 (W) ${\times}$ 2 (H) cm) and 1 exhaust fan (50 (D) cm), and simulated using CFD code, FLUENT. The simulation results for the original weaning piglet house showed ununiform ventilation for each room. Therefore, to uniformly ventilate all rooms, the heights of the air inlet and first fence were modified to 3 cm and 100 cm, respectively. The simulation result f3r the modified weaning piglet house showed uniform ventilation for all rooms and the optimum air inlet velocity of 1.4 m/s.

• Journal of Biosystems Engineering
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• 제35권6호
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• pp.434-442
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• 2010

This study was carried out to determine necessary conditions for optimal ventilation of small windowless piglet house (4.0 (W) $\times$ 11.0 (L) $\times$ 2.6(H) m) with corridor and attic for preheating using CFD (Computational Fluid Dynamics) simulation. The experimental weaning piglet house was consisted of a corridor, an attic, 4 rooms (3.0 (W) $\times$ 2.75(L) m), 3 fences (0.7(H) m), 5 air inlets and 2 exhaust fans (0.4 (D) m) and simulated using CFD code, FLUENT. The simulation results for the experimental weaning piglet house showed that each room was uniformly ventilated under all the experimental conditions and air velocities at 0.1 m above floor are less than 0.15 m/s for 0.75 m/s and 1.0 m/s of air inlet velocity but 0.61 m/s for 1.25 m/s. The simulation results are similar to the measured results. Considering the air flow pattern, ventilating efficiency, air velocity at 0.1 m above floor and cold stress of weaning piglets and so on, the optimum velocity of air inlet might be 1.0 m/s.

• 한국환경농학회지
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• 제27권2호
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• pp.150-155
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• 2008

본 연구는 입기구가 11개이고 배기구가 9개인 무창이유자돈사에 대하여 CFD 시뮬레이션을 실시함으로써 겨울철 최적 환기를 위한 입 배기구의 위치와 개수 및 최적 공기 유입속도를 구명하고자 수행되었다. 배기팬에 가까운 돈방의 경우에는 나머지 돈방에 비해 상대적으로 음압이 크기 때문에 환기가 많이 되는 것으로 나타났고, 나머지 돈방의 경우에는 음압이 작아 환기가 적게 되는 것으로 나타났다. 이런 이유로 동일 면적의 입기구를 설치함에 있어서 같은 간격으로 배치하면 환기가 불균일하게 이루어지기 때문에, 배기팬에 가깝게 위치한 돈방에서는 입 배기구를 나머지 돈방에 비해 적게 만들어 주거나 간격을 넓게 만들어 줌으로써 균일한 환기를 할 수 있는 것으로 분석되었다. 특히 입기구가 11개이고 배기구가 9개인 무창돈사의 경우에는 동일 선상에 있는 입기구 4개를 폐쇄하며 배기구 1개는 완전 폐쇄하고 2개는 2/3를 폐쇄하였을 때 환기가 균일하게 되는 것으로 나타났다. 또한 실험돈사와 같이 돈사의 폭이 3 m 정도일 경우에는 입기구의 입공기 속도가 0.5 $m\;sec^{-1}$ 정도로 유지될 때 틈바닥 위 0.1 m 높이 위치의 풍속이 적정수준으로 유지되는 것으로 나타났다.

• Journal of Animal Science and Technology
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• 제62권2호
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• pp.218-226
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• 2020

The present study investigated the effects of loose farrowing type during gestation and after farrowing on reproductive performance and of lactating sows. A total of 22 primiparous sows (Landrace; average initial body weights [BW], 228.54 ± 12.79 kg) were allotted to one of two treatments on the basis of body weight. Sows were divided into two experimental groups, conventional farrowing crates (CON), and loosed-farrowing pens (LFP). The experiment duration was around 38 days ranging from 10 days before parturition to 28 days after parturition. Gestating sows at the age of 105 d were placed in gestational stalls (group housing). All the sows were fed a common diet according to the National Research Council requirements for lactation. Cross-fostering was performed within 1 day of parturition. From 1 day after weaning, estrus detection was performed twice-daily (0900 and 1730 h) for 10 min by boar exposure. There were significant effects of LFP housing type on the farrowing duration, and farrowing interval. At the farrowing time, none of the litter parameters including total born, stillborn, mummy, born alive piglets and total litter weight and piglet weight were affected. There were no effects of housing type on the mortality of piglets at d 1, 3, 7, 21, and 28. In conclusion, the result of this study showed that there is no performance difference between the crated or LFP sows, which indicate that the LFP housing has the potential to be used as an alternative to the crated house without any detrimental effects in reproduction performance of lactating sows.