The study of double-diffusive convection has received considerable attention during the last several decades since this occurs in a wide range of natural settings. The origins of these studies can be traced to oceanography when hot salty water lies over cold fresh water of a higher density resulting in double-diffusive instabilities known as “salt-fingers,” Stern (35; 36). Typical technological...

Passive heat transfer from enclosures with rectangular fins is studied both experimentally and theoretically. Several sample enclosures with various lengths are prepared and tested. To calibrate the thermal measurements and the analyses, enclosures without fins (“bare” enclosures) are also prepared and tested. Surface temperature distribution is determined for various enclosure lengths and heat...

conv hAs (Ts T ) where As is the heat transfer surface area and h is the convection heat transfer coefficient. When the temperatures Ts and T are fixed by design considerations, as is often the case, there are two ways to increase the rate of heat transfer: to increase the convection heat transfer coefficient h or to increase the surface area As. Increasing h may require the installation of a p...

The use of natural convection, side-arm heat exchangers in solar domestic water heating systems is becoming a popular method of reducing system cost and electric demand. In this paper, we compare thermal performances of three natural convection heat exchangers mounted along the outside of the water storage tank and a commercial wraparound-tank heat exchanger to two forced-flow heat exchangers. ...

The liquid motion induced by surface tension variation, termed the thermocapillary or Marangoni effect, and its contribution to boiling heat transfer has long been a very controversial issue. In the past this convection was not the subject of much attention because, under terrestrial conditions, it is superimposed by the strong buoyancy convection, which makes it difficult to obtain quantitativ...

in this paper, free convection in an inclined stepped chamber has been studied. one wall of this enclosure is kept cold and the opposite wall equipped with constant heat source. the remaining walls are maintained adiabatic. there is one adiabatic step on the bottom wall. the aim of the present study is to forecast the effect of raleigh number, slope of enclosure, step dimension, and heat source...

this paper presents a three-dimensional numerical investigation carried out in turbulent forced convection in a tube with helical ribs. enhancement of heat transfer using helically corrugated tubes has beenstudied experimentally by many researchers but there exist a few published numerical analyses results. the paper also introduces the results of heat transfer and friction factor data for inco...

The forced convection experiment of fan plate-finned tube heat exchangers which are mainly used in air conditioners and the forced convection model have been studied for which the heat transfer effect of this type exchangers has not been proposed by a model. All measurements were made when there is no refrigerant flow in the pipe at Reynolds's number of 580. According to the experiment results,...

Natural convection heat transfer was investigated experimentally in a concentric-cylinders annulus. To enhance the rate of heat transfer, pin fins were installed on the surface of the inner cylinder. Two fin arrangements were employed, namely, staggered and in-line arrangements. The length of the fins varied from 2 to 8 cm and the Rayleigh number Ra changed in the range from 5 x 105  to 5 x 106...

Laminar natural convection in differentially heated (β = 0°, where β is the inclination angle), inclined (β = 30° and 60°), and bottom-heated (β = 90°) square enclosures filled with a nanofluid is investigated, using a two-phase lattice Boltzmann simulation approach. The effects of the inclination angle on Nu number and convection heat transfer coefficient are studied. The effects of thermophor...