water heater

NUMERICAL DATA FOR MICROWAVE WATER HEATER

For a WR 340 heat transfer of height b with a liquid slab of thickness e, ß or be/ß is the physical constant which governs the microwave water heating process [4], [7] :

ß = 7.35 e 230 dB.° C/m = 1.690 e dB.° C/mm = 0.194 e °C/mm where e is in mm.

be/ß = 222,5 mm³/°C

Using experimental data To and DT, the values of z*, V* and Dz/z* can be deduced through the data given in Figs.1 and 2 in conjunction with the above formulae. d is a fraction of the total temperature variation DT.

Fig. 1
Approximate conjugate d ratio along the length of the heat tranfer.

For d = 0.990
z* = 4.6 To/2ß, V* = 4.6 v = 4.6 beTo/2ß
For d = 0.999
z* = 6.9 To/2ß, V* = 6.9 v = 6.9 beTo/2ß

1-d

z* in unit of To/2ß

Fig. 2
d ratio dependence on the relative error.

For d = 0.990
Dz/z* = DV/V* = 0.78 DT/To
For d = 0.999
Dz/z* =DV/V* = 0.85 DT/To

DT is related to the process parameters with the formula :

DT ° C = 3.79 (KW required)/GPM

d

Dz/z* in unit of DT/To

Fig. 1 Approximate conjugate d ratio along the length of the heat tranfer. For d = 0.990 z* = 4.6 To/2ß, V* = 4.6 v = 4.6 beTo/2ß For d = 0.999 z* = 6.9 To/2ß, V* = 6.9 v = 6.9 beTo/2ß	1-d
		z* in unit of To/2ß


Fig. 2 d ratio dependence on the relative error. For d = 0.990 Dz/z* = DV/V* = 0.78 DT/To For d = 0.999 Dz/z* =DV/V* = 0.85 DT/To DT is related to the process parameters with the formula : DT ° C = 3.79 (KW required)/GPM	d
		Dz/z* in unit of DT/To