Dual cycle

The operation of the reciprocating internal combustion engines represents a compromise between the Otto and the Diesel cycles, and can be described as a dual combustion cycle. Heat transfer to the system may be considered to occur first at constant volume and then at constant pressure. Such a cycle is called a dual cycle. 

The Dual cycle as shown in Fig. 3.20 is composed of the following five processes ... 

Pressure and temperature at the start of compression in a dual cycle are 14.7 psia and 540°R. The compression ratio is 15. Heat addition at constant volume is 300Btu/lbm of air, while heat addition at constant pressure is 500 Btu/lbm of air. The mass of air contained in the cylinder is 0.03 Ibm. Determine (1) the maximum cycle pressure and maximum cycle temperature, (2) the efficiency and work output per kilogram of air, and... 

What five processes make up the dual cycle ... 

The combustion process in internal combustion engines as an isobaric or isometric heat-addition process is oversimplistic and not realistic. A real cycle p-v diagram of the Otto or Diesel cycle looks like a curve (combination of isobaric and isometric) rather than a linear line. Are the combustion processes in the dual cycle more realistic ... 

Adding a turbocharger and a precooler to a dual cycle is proposed as shown in Fig. 3.46a. The cylinder volume of the engine is 0.01 m. Evaluate the proposed cycle. The basic dual cycle and the proposed turbocharger and precooler dual cycle information is ... 

Figure 3.46b Turbocharger and precooler dual cycle input.

Figure 3.46d Dual cycle without result turbocharger and precooler.

It is observed that both the cycle efficiency and MEP of the proposed cycle are better than those of the dual cycle without turbocharger and precooler. 

Heat engines that use gases as the working fluid in a closed-system model were discussed in this chapter. The Otto, Diesel, Miller, and dual cycles... 

The dual cycle involves two heat-addition processes, one at constant volume and one at constant pressure. It behaves more like an actual cycle than either the Otto or Diesel cycles. 

Wu, C. and Blank, D.A., The effect of combustion on a power optimized endo-reversible Dual cycle. International Journal of Power and Energy Systems, 14(3), 98-103, 1994. 

Scheme 2 Dual cycle mechanism for the Sonogashira protocol...

System Type. The three basic types of SCF cleaning systems are the direct system, in which supercritical carbon dioxide (SCCO2) is the only cleaning solvent, the single-cycle system, in which the SCCO2 is mixed with a cosolvent and the dual-cycle system in which the parts are exposed separately to cosolvent and supercritical carbon dioxide. 

In the dual-cycle system, all steps take place in a single vessel. The cosolvent is first introduced from a separate module into the cleaning vessel at a selected temperature and atmospheric pressure and circulated around the work to dissolve the contaminant. Then the... 

The dual-cycle system is favored over the single cycle system if the cleaning process requires the use of cosolvent. Although the cosolvent reclaim system adds to initial capital costs, it yields a net gain by lowering material costs and improving consistency and operating efficiency. 

The second process investigated was an alternative for a xylene cleaning process. The dual-cycle (two step) process, as described previously in this chapter, is used due to the nature of the contaminant being removed. Figure 7 shows a bar chart of the annual costs (normalized) for the two processes. Once again the key differences are in the equipment and consumables. 

Process and equipment developments continue to make supercritical carbon dioxide cleaning a more competitive option and to expand the applications for this process. These developments are primarily aimed at reducing the requirements for continuous carbon dioxide flow, producing effective cleaning at lower temperatures and pressures, and the construction of equipment with less expensive materials. These objectives are being reached primarily because of improved understanding of the effectiveness of carbon dioxide as a solvent and the required performance of the equipment. It appears that the dual-cycle (two step) process will continue to receive primary attention as the most effective supercritical carbon dioxide alternative to conventional cleaning methods. 

Ust, Y., Sahim, B., Sogut, O.S. (2005). Performance analysis and optimization of an irreversible dual-cycle based on an ecological coefficient of performance criterion. 

Ground rubber particles are subjected to a dual cycle of magnetic separation, then screened and recovered in various size fractions... 

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