Below this temperature the flow resistance due to increasing viscosity (and possibly long hoses with quick connectors) is too high for proper cooling performance. Such liquids can be used for flow temperatures down to -25☌, depending on the application the thermostat is used for. The kinematic viscosity of water is water 1. The SI unit for water kinematic viscosity is square meter per second (m 2 /s). The CGS units refer to poise (P, or g cm-1 s-1 0.1 Pa s) and is commonly expressed as centipoise. Mixtures with lower antifreeze content have also lower viscosity, which leads to less flow resistance and less load of the thermostat's pump. Water flows from a large reservoir through a fluid motor and gate valve at a rate of 1000 lites/min (Figure 2). The most interesting physical properties in terms of the treatment of water are density, Thermal properties, viscosity, Surface tension, Electrical and. The SI unit for dynamic water viscosity is Newton second per square meter (N s 2 /m and can be expressed in Pascal-second (Pa s) as well. Other mixtures are 30:70 or 20:80 of antifreeze : water (% by volume). Viscosity can be conceptualized as quantifying the internal frictional force that arises between adjacent layers of fluid that are in relative motion. For liquids, it corresponds to the informal concept of 'thickness': for example, syrup has a higher viscosity than water. Most antifreezes contain corrosion inhibitors and other additives, like foam depressants.īesides its use in radiator systems, automotive antifreeze mixed with water is also a heat transfer liquid for cooling thermostats or circulators used in labs.Ĭommon mixtures are 50:50 or 40:60 of antifreeze : water. The viscosity of a fluid is a measure of its resistance to deformation at a given rate. Dynamic and Kinematic Viscosity of Water in Imperial Units (BG units): Temperature - t - (oF)-5 Dynamic Viscosity - (lb s/ft2) x 10 Kinematic Viscosity - (ft2/s) x 10-5 32 3.732 1.924 40 3.228 1.664 50 2.730 1.407 60 2.344 1.210 70 2.034 1.052 80 1.791 0.926 90 1.500 0.823 100 1.423 0.738 120 1.164 0.607 140 0.974 0.511 160 0.832 0.
A further task is to lubricate the cooling system, such as the water pump. Automotive antifreeze keeps the cooling water from freezing in winter and from boiling in summer. The main ingredient in most coolants is ethylene glycol or propylene glycol. Automotive antifreeze, also called coolant, is the liquid which is used in the radiator and cooling system of an internal combustion engine for vehicles.
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