![]() ![]() Replace v with the given u, h, or s in the flow chart, Figure 2.4.3. The procedure is exactly the same as for case 3. ![]() Figure 2.4.3 Flow chart for determining fluid properties from thermodynamics tables if T and v are knownĬase 4: temperature T and one of u, h and s are given. You may draw a T-v diagram (see Figure 2.3.4) to help you better understand the flow chart in Figure 2.4.3. Figure 2.4.2 Flow chart for determining fluid properties from thermodynamic tables if T and x are knownĬase 3: both T and v are given. You may draw a T-v diagram (see Figure 2.3.4) to help you better understand the flow chart in Figure 2.4.2. Figure 2.4.1 Flow chart for determining fluid properties from thermodynamic tables if P and T are knownĬase 2: both T and x are given. You may draw a P-T diagram (see Figure 2.3.2) to help you better understand the flow chart in Figure 2.4.1. The following flow charts demonstrate the procedure.Ĭase 1: both T and P are given. To determine the fluid properties at a certain state, we will need to know two intensive properties from this list: P, T, v, u, h, s, and x. ![]() How do we determine if a fluid is a compressed liquid, superheated vapour, or two-phase liquid- vapour mixture ? How do we find the fluid properties at a certain state? By examining the tables in Appendices A-D, you probably have noticed that all properties in these tables are intensive properties. To avoid unnecessary confusion and to reduce the chance of errors, thermodynamic tables from the same source should be used in calculations because, in most thermodynamic analyses, we are concerned about the changes in specific internal energy, specific enthalpy, and specific entropy, or \Delta u, \Delta h, and \Delta s. This may cause inconvenience or errors when performing calculations. Because the values of u, h, and s strongly depend on the reference state, it is not surprising to see different values of u, h, and s from different sources. It is important to note that thermodynamic tables can be generated with respect to different reference states. The reference state s for the tables in this book are clearly stated in A ppendices A-D. Among those thermodynamic properties, P, T, and v are measurable properties, and u, h, and s cannot be measured directly t hey are calculated with respect to predefined reference states. ![]() In these tables, the specific volume, specific internal energy, specific enthalpy, and specific entropy are tabulated as functions of the pressure and temperature. Table A3 is the compressed liquid table for water. Tables A2, B2, C2, and D2 are the superheated vapour tables for find ing the properties of the fluid s in the superheated vapour region. They are used to find the properties of the corresponding fluid s in saturated liquid, saturated vapour, and two-phase regions. Tables A1, B1, C1, and D1 are the tables for the saturated fluids. The data in these tables are obtained from NIST Chemistry WebBook, SRD 69, which consists of the thermophysical properties of various common fluids.Īppendix A: Thermodynamic Properties of WaterĪppendix B : Thermodynamic Properties of AmmoniaĪppendix C : Thermodynamic Properties of R134aĪppendix D : Thermodynamic Properties of Carbon Dioxide This book includes t he tables for four pure substances : water, ammonia, R134a, and carbon dioxide. Thermodynamic tables are commonly used to determine the properties of a substance at a given state. ![]()
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