Studies on the Mass Tsansfer Coefficient on the Body Surface of Livestock (III)
The Mass Transfer Coefficient of Water on the Body Surface of Swine
1988 Volume 18 Issue 3 Pages 12-22
Details
1988 Volume 18 Issue 3 Pages 12-22
The author evaluated the mass transfer coefficients of sweat on the body surface of cattle in previous paper. In this paper, these values were determined for swine.
The author made a one-third scale model of swine weighing 50kg from the relation of live weight to diameter or body segment length. The mass transfer coefficient of a body segment was evaluated using this model and the trunk of live swine. The method of measurement in using this model was the same way as that in the previous paper, but the measurement of the mass transfer coefficient of a trunk of live swine was made according to the method of Nishi et al. developed, using a naphthalene ball.
The results obtained are summarized as follows;
1) 21 heads of swine weighing 5-131.8kg were evaluated for the relation between weght and length or diameter of a body segment. It was found that a 50kg live weight is the diverging point due to the drop in elongation percentage of body segmental diameter or length at a live weight above 50kg (Table 2).
2) Assuming the head, upper arm and thigh to be circular cores, the trunk a cylinder and half sphere, and the fore arm and leg cylinders, we evaluated the body segmental surface area of the swine. The evaluated area for live weight had an error percentage of only -9--4% as determined by Brody's equation (A=0.0974W0.633).
3) The ratio of body segmental surface area to that of the entire body was approximately as follows: trunk: 67%, head: 10%, upperarm: 3%, forearm: 2%, thigh: 3.5%, and leg: 2% (Table 3).
4) The relation between Sh/Sc1/3 and Re in the trunk and leg was not affected by swine orientation toward a stream of air, other body segments were affected by this stream when the Reynolds number was low (Table 5).
5) The mass transfer coefficient of sweat over the entire body surface increased with air stream velocity, but was not affected by swine orientation toward this stream (Table 6).
6) The mass transfer coefficient of sweat on the trunk of live swine tended to exceed that in experiment using the present model. This was considered due to thoracic movement necessary for respiration (Table 7).
7) However, swine sweat so little that its significance may be convective heat transfer coefficient can be detemined by the Lewis relationship.
