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Grashof number. In fluid mechanics (especially fluid thermodynamics ), the Grashof number ( Gr, after Franz Grashof [ a]) is a dimensionless number which approximates the ratio of the buoyancy to viscous forces acting on a fluid. It frequently arises in the study of situations involving natural convection and is analogous to the Reynolds number ...
Differential scanning calorimetry ( DSC) is a thermoanalytical technique in which the difference in the amount of heat required to increase the temperature of a sample and reference is measured as a function of temperature. [ 1] Both the sample and reference are maintained at nearly the same temperature throughout the experiment.
Operating temperature. An operating temperature is the allowable temperature range of the local ambient environment at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum ...
The thermal boundary layer thickness is customarily defined as the point in the boundary layer, , where the temperature reaches 99% of the free stream value : such that = 0.99. at a position along the wall. In a real fluid, this quantity can be estimated by measuring the temperature profile at a position along the wall.
Chart showing flat-plate collectors outperforming evacuated tubes up until 67 °C (120 °F) above ambient and, shaded in gray, the normal operating range for solar domestic hot water systems. [ 13 ] In most climates, flat plate collectors will generally be more cost-effective than evacuated tubes. [ 14 ]
A medical/clinical thermometer showing the temperature of 38.7 °C (101.7 °F) Temperature measurement (also known as thermometry) describes the process of measuring a current temperature for immediate or later evaluation. Datasets consisting of repeated standardized measurements can be used to assess temperature trends.
Water is the chemical substance with chemical formula H 2 O; one molecule of water has two hydrogen atoms covalently bonded to a single oxygen atom. [25] Water is a tasteless, odorless liquid at ambient temperature and pressure. Liquid water has weak absorption bands at wavelengths of around 750 nm which cause it to appear to have a blue color. [3]
Thermal comfort is the condition of mind that expresses subjective satisfaction with the thermal environment. [ 1] The human body can be viewed as a heat engine where food is the input energy. The human body will release excess heat into the environment, so the body can continue to operate. The heat transfer is proportional to temperature ...