Ap

2fG2L gpDe

To solve these equations for a particular duty it is necessary to know G, L, and De, and it is shown below how these can be eliminated to produce a general equation. For any plate,

where m is the total mass flow rate and At the total flow

That is, the film heat-transfer coefficient is expressed only in terms of the surface area and equivalent diameter. A computer program solves equation A8 using a constant value of De and using an empirical factor Z to account for port pressure loss and other deviations from equations A2-A4. The equation is solved using the HTU approach where

UAS m1c1

That is, the number of heat-transfer units is the temperature rise of fluid 1 divided by the mean temperature difference.

U is defined as

De is defined by APV as four times the flow area in a plate divided by the wetted perimeter. Since the plate gap is small compared with the width, then:

where hr and h2 are calculated from an empirical modification of the constants in equation A8. The powers in equation A8 are not modified.

4 X Af wetted perimeter

but since As = L X wetted perimeter where As is the total surface area:

and it is possible to eliminate L from equation A4.

Similarly, by substituting G using equation A5 in equations A2, A3, and A4 and then by rearranging the equa-

Homemade Pet Food Secrets

Homemade Pet Food Secrets

It is a well known fact that homemade food is always a healthier option for pets when compared to the market packed food. The increasing hazards to the health of the pets have made pet owners stick to containment of commercial pet food. The basic fundamentals of health for human beings are applicable for pets also.

Get My Free Ebook


Post a comment