Question

7–110 Write an article on forced convection cooling with air, helium, water, and a dielectric liquid. Discuss the advantages and disadvantages of each fluid in heat transfer. Explain the circumstances under which a certain fluid will be most suitable for the cooling job.

Answer 1

bata from the giren question (0) Forced convection comes into picture when the natural convection heat transfer effectiveness is very poor for heal transfer, are using and scing the effect of forced various fluids sexh as helium, watco, dio and dielectric fluid. we There convection on * Air: by using forced convection, that as just by adding for and blousing aio, the heat transfer weftivent can be ag ongreased to many time. here is no contraint on availa bility of arygen it 98 available in abunclance. can be used * helium · It has high heat transfer coefficients 34 has a very simple design and 1130 as an apparatus for kap teeping things cool. · one such disadvantage. Os that it has lack of expenence in utilizing forced convoc tion cookd supceondueting coils.

* it has . water: water has a high heat capacity as a specific heat value © = 4180 Jlng k hence it can carly high amount of heat Disadvantage of wales: cooling system ºs that these 9s always a danger of corrosion and the another disadvantage is the problem of maintanance. water cooling as mainly czployed ºn automobile gnlernal combustion engines, radiator, chemical plants and also Petroleum &c fi nerics * biclectric fluids • A dielectric flid is a liquid which as poor conductor of electricity but a good supporter of an electrostatic field · when an electronic component 93 9mmereselin a liquid medium, The Temperature through out 98 uniform It is also has a very high heat transfer coefficents in this the sale of heat transfer is also high very