RÜZGAR HIZI VE YÖNÜ İLE HAVA ÇIKIŞ AÇIKLIĞI TİPİNİN HAVALANDIRMAYA OLAN ETKİStNÎN KAPALI SIĞIR BARINAĞI MODELİNDE İNCELENMESİ ÜZERİNE BİR ARAŞTIRMA

Abstract

OZET Bu arastirma, 30 baslik kapali ve durakli sut sigiri ahirinin 1/20 olcekli modeli uzerinde yapilmistir. Ruzgar hizi ve yonu ile farkli 4 tipte planlanan mahya hava cikis acikliklarinin model ici hava dagilimina ve havalandirma miktarina olan etkisi arastirilmistir. Arastirma laboratuvar kosullarinda yapilmis olup ruzgar tunelinden saglanan degisik yonlerden esen farkli ruzgar hizlari ile mahya hava akim hizlan ve model ici ve disi arasindaki sicaklik farklariyla olan iliskileri belirlenmistir. Arastirmadan elde edilen sonuclara gore, mahya acikliginin sekli, ruzgar yonu ve yapinin konumu mahya hava akim hizini onemli olcude etkilemektedir. Dikdortgen orifis seklinde planlanan mahya aciklik tipi, diger tiplere oranla daha uygun havalandirma saglamaktadir. RIDGE VENT, WIND DIREKTION AND WIND VELOCITY EFFECTS ON CLOSED, NATURALLY VENTTLATED, CATTLE BUILDlNG VENTILATION SUMMARY Naturally ventilated buildings used for cattle production hava various ridge vent configurations. Information pertaining to the ventilation characteristics ofdifferent geometrically shaped ridge vent is limited. Therefore, the effects ofwind speed, wind direction and ridge vent shape were studied in a model (1/20 scale) on ventilation characteristics, naturally ventilated, dairy cattle building. A simple wind tunnel was built to develop an airflow pattern. Wind was simulated by variable speedfans. Wind speed varied between 0 to 7 mJs. The construction of the model was based on a geometric lenght scale of 20, and the assumption was t hat the samefluid and material would be used in the model and prototype, Trusses, purlins, poles, sides and roof were made of wood. The end walls were constructed with plexiglass for the purpose ofvisual observation of airflow patterns. The four ridge vents were constructed by using galvanized metal. Principles of similitude and dimensional analysis were utilized in deriving a set of independent and dependent Pi terms, From the defination of the Buckingham Pi Theorem a set of14 dimensionless Pi terms were obtained (Langhaar, 1983). The sdudy descr 'ibed in this paper was conducted to determine which type of ridge vent would be suitable for naturally ventilated dairy barns in cold regions. Resuits indicated that ridge vent design has a significant effect on outled velocity and wind velocity. Temperature difference was affected by ridge vent geometry and vind velocity. The baffled (Type II) ridge vent had the highest outlet velocity when ali wind directions were considered, while covered (Type III) ridge vend produced the lowest outlet velodties. AUhough the covered ridge vent produced the largest temperature differences, the associated low outlet velodties make it the least desirable of the four ridge vents tested.