A teapot with a brewer at the top is used to brew tea, as shown in Fig. P3–143. The brewer may partially block the vapor from escaping, causing the pressure in the teapot to rise and an overflow from the service tube to occur. Disregarding thermal expansion and the variation in the amount of water in the service tube to be negligible relative to the amount of water in the teapot, determine the maximum coldwater height that would not cause an overflow at gage pressures of up to 0.32 kPa for the vapor.
A teapot with a brewer at the top is shown in the picture below .The brewer partially block the vapor from escaping cause the pressure in the teapot to rise will lead to overflow.The maximum pressure that rise in the teapot will will not cause overflow is 0.032 kPa.
Step 1 The cold water temperature is 200 C
The density of water at 200 C ,ρw= 998 kg/m3
The distance from the bottom of the teapot to the end of the service tube is
h1 =3 + 12 Cos350
h1 =3 + 12 (0.8192)
h1= 12.8 cm
The maximum pressure in the teapot which will not cause overflow is
P1 = ρwg
is the change water level
=0.033 m =3.3 cm