Entransy analyses of heat–work conversion systems with inner irreversible thermodynamic cycles

In this paper, we try to use the entransy theory to analyze the heat–work conversion systems with inner irreversible thermodynamic cycles. First, the inner irreversible thermodynamic cycles are analyzed. The influences of different inner irreversible factors on entransy loss are discussed. We find that the concept of entransy loss can be used to analyze the inner irreversible thermodynamic cycles. Then, we analyze the common heat–work conversion systems with inner irreversible thermodynamic cycles. As an example, the heat–work conversion system in which the working fluid of the thermodynamic cycles is heated and cooled by streams is analyzed. Our analyses show that larger entransy loss leads to larger output work when the total heat flow from the high temperature heat source and the corresponding equivalent temperature are fixed.Some numerical cases are presented, and the results verify the theoretical analyses. On the other hand, it is also found that larger entransy loss does not always lead to larger output work when the preconditions are not satisfied.

An effective thermodynamic transformation analysis method for actual irreversible cycle

An effective thermodynamic transformation analysis method was proposed in this study. According to the phenomenon of ex- ergy consumption always coupling with heat transfer process, the effective thermodynamic temperatures were defined, then the actual power cycle or refrigeration/heat pump cycle was transformed into the equivalent reversible Carnot or reverse Carnot cycles for thermodynamic analysis. The derived effective thermodynamic temperature of the hot reservoir of the equivalent reverse Camot cycle is the basis of the proposed method. The combined diagram of TR-h and TR-q was adopted for the analy- sis of the system performance and the exergy consumption, which takes advantage of the visual expression of the heat/work exchange and the enthalpy change, and is convenient for the calculation of the coefficient of performance and exergy con- sumptions. Take a heat pump water heater with refrigerant of R22 for example, the proposed method was systematically intro- duced, and the fitting formulas of the effective thermodynamic temperatures were given as demonstration. The results show that the proposed method has advantage and well application foreground in the performance simulation and estimation under the variable working conditions.

Optimal Performance Characteristics of Subcritical Simple Irreversible Organic Rankine Cycle

Based on the theory of finite time thermodynamics, a subcritical simple irreversible organic Rankine cycle(SSIORC) model considering heat transfer loss and internal irreversible losses is established in this paper. The total heat transfer surface area is taken as a constraint, and R245fa is adopted as working fluid of the cycle in the performance optimization. The evaporator heat transfer surface area and mass flow rate of the working fluid are optimized to obtain the maximum power output and thermal efficiency of the SSIORC, respectively. In addition, the influences of the internal irreversibilities on the optimal performances are also investigated. The results show that when the evaporator heat transfer surface area is varied, the relationship between power output and thermal efficiency is a loop-shaped curve, and there exist maximum power output and thermal efficiency points, respectively. However, the two maximum points are very close to each other. When the mass flow rate of the working fluid is varied, the relationship between power output and thermal efficiency is a parabolic-like curve. With the decreases of expander and pump irreversible losses, the performances of the irreversible SSORC are close to those of the endoreversible SSORC with the only loss of heat transfer loss.

Repurposing cancer drugs to treat neurological diseases–Src inhibitors as examples

Aberrant cell cycle diseases：The cell cycle is an irreversible,ordered set of events that normally leads to cellular division,consisting of quiescent state（G0）,the first gap phase（G1）,DNA synthetic phase（S）,the second gap phase（G2）and mitosis phase（M）.After the cell has split into its two daughter cells,the new cells enter either G1 or G0.

Entransy analyses of the thermodynamic cycle in a turbojet engine

The analysis and the design of turbojet engines are of great importance to the improvement of the system performance.Many researchers focus on these topics,and many important and interesting results have been obtained.In this paper,the thermodynamic cycle in a turbojet engine is analyzed with the entransy theory and the T-Q diagram.The ideal thermodynamic cycle in which there is no inner irreversibility is analyzed,as well as the influences from some inner irreversible factors,such as the heat transfer process,the change of the component of the working fluid and the viscosity of the working fluid.For the discussed cases,it is shown that larger entransy loss rate always results in larger output power,while smaller entropy generation rate does not always.The corresponding T-Q diagrams are also presented,with which the change tendencies of the entransy loss rate and the output power can be shown very intuitively.It is shown that the entransy theory is applicable for analyzing the inner irreversible thermodynamic cycles discussed in this paper.Compared with the concept of entropy generation,the concept of entransy loss and the corresponding T-Q diagram are more suitable for describing the change of the output power of the analyzed turbojet engine no matter if the inner irreversible factors are considered.