Features of Thermo Dynamics. (Thermodynamic properties)
essential to analyze the heating system is to define the properties of Thermo Dynamics with boundaries (boundary) refers to the characteristics of the object. Or compounds that can be measured, such as the size, temperature, pressure and density. A property segment and the heat exchanger. We can measure the change in the form of property. But not the property itself. In other words, Features of the "A" in a while, and the heat is "done" with the property changes. We have the car to measure the size of the work and the heat of the boundary (boundary) of the system and the amount of energy transfer are more or less dependent on the dynamics of the property that was like
the Thermo Dynamics with. centered on energy Features of Thermo Dynamics all so intertwined with energy and environment (state) of thermoplastic dynamic of the system is determined by the value of the property. In normal conditions We can determine the state of a system with two built-in independent steam at a temperature of 125, as the atmospheric pressure. But in a system with more than one state, such as dry air and steam. Identifies the conditions that may be qualified to know if we can identify the three conditions of the substance or has already. It is possible to know the value of other properties that do not depend on each
property Thermo Dynamics of interest are discussed herein, including temperature, pressure, density, specific volume (specific volume) heat (specific. heat) enthalpy (enthalpy) entropy (entropy) and features liquid and vapor (liquid -vapor property of state)
temperature. (Temperature: t)
as an indicator of the temperature of the thermal conditions. And the ability to exchange Energy and chemical substances when brought in contact with. The substance has a higher temperature to transfer energy to the substance at a temperature lower than the SI unit used Celsius (0C) a thermometer. With reference to the freezing point of water (00C) and the boiling point of water. (1000C)
absolute temperature (Temperature: T)
is a number that a degree above the absolute zero (absolute zero) values with Kelvin (K), where T = 10C + 273, so the temperature difference of the two scales so. are equal Which can be used interchangeably
pressure (Pressure: P)
is perpendicular to the fluid force acting on the first unit in the direction against the force. Full pressure The pressure above the zero point pressure gauges to measure pressure above atmospheric pressure. The unit used to measure the pressure in the system is newtons per square meter (N / m2) or called Pascal (Pascal, Pa) Newton is a unit used to measure force (N) standard pressure there. value = 101.3 kPa (14.7 psia) tool used to measure pressure, including pressure gauges and manometer
thickness Nancy. And specific volume (Density and specific volume: , v)
density is determined by the mass divided by volume. While the specific volume Obtained by dividing the volume by the mass density and specific volume. The proportion To each other The density of air at standard pressure and 250C is approximately equal to 1.2 kg / m3
Specific heat (Specific heat: Cp)
specific heat of a substance is defined as the amount of energy needed to make one unit mass of it. temperatures rise one degree units (1 K) specific heat based on the same second the specific heat at constant volume (Specific heat at content volume, Cv), and specific heat at constant pressure (Specific heat at. content pressure, Cp), which the latter will be discussed more. Because it can Applies to the processes that are taking place in cooling. And air
enthalpy (Enthalpy: h)
if the movement constant pressure as in Example 1.2 jobs occurred. The size of the heat added Or removed per unit mass. Will the change in enthalpy of the substance. We can find the enthalpy of a substance from multiple tables and charts (charts) which the enthalpy These are the basic reference. Choosing a given (datum plane) to any criteria, such as datum plane of water and steam, the enthalpy is zero (0) for the 00C by the fundamentals underlying this enthalpy of water at 1000C will. the 419.06 kJ / kg and steam 1000C will be 2676 kJ / kg
entropy (entropy: s)
even if it is very difficult to define the term entropy, since it relies on descriptions of many important either. techniques and philosophies, but we can use this feature to identify. And determines the behavior of the material as well. We can read the entropy of the table. Chart properties like enthalpy are mentioned in the resolution of the base are connected to these two properties, namely: 1. If the gas or vapor is compressed (compressed) or expanded (expanded) form. no friction, without adding or removing heat during the process, then the entropy of the substance is considered to be constant movement in Article 2. according to one variation of enthalpy. The place shows the amount of work (work) per unit mass required for compression. Or even out of the expansion, it is possible that the use of a toll on most years it is to read the lines on the graph entropy constant. To calculate the compression The vapor compression refrigeration system. (Vapor-compression refrigeration cycles)
properties of the liquid - vapor (Liquid -vapor properties)
, thermal systems, most substances circulating in the cycle will change state between a liquid state and a vapor pressure, temperature, and enthalpy to the property. the key to this change. The relationship between these properties Are shown in Table Or on the chart, such as chart pressure and end.
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