The Humphrey/Atkinson thermodynamic cycle has been analyzed and compared to the Otto, Diesel, and Brayton cycles. It was shown that for the same initial conditions and peak cycle temperature the thermal efficiency of the Humphrey/Atkinson cycle exceeds that of the others as a result of the reduction in entropy production due to the volumetrically confined combustion, particularly for lower compression ratios. The expression for thermal efficiency has been derived and it has been shown that the net work includes not only compression and expansion work, but also an additional flow work term. A transient model for the Wave Disk Engine which is not restricted to isentropic compression and expansion processes is developed and an expression for the efficiency is presented.

A wound composite material wheel has been developed and is intended to be used for many purposes. One of these applications is marine current turbine. Diffuser-augmented turbines are capable of concentrating the energy in water. If a diffuser shaped shroud encloses a conventional horizontal axis turbine, the low pressure at the exit of the diffuser draws a larger mass flow through the turbine. This permits more power to be extracted from the water. In this paper, numerical analysis of a diffuser-augmented composite material marine current turbine (CMMCT) is developed and compared with a conventional bare turbine. The CFD results show that the extracted power of a diffuser-augmented CMMCT can be 5 times larger than the power extracted by a bare turbine of the same turbine area. The results of the analysis provide an insight into the hydrodynamic design and operation of a diffuser-augmented turbine in order to shorten the design period and improve technical performance.

Advanced composite materials are widely used as marine current turbines due to their high strength-to-weight ratios and excellent resistance to corrosion. A novel manufacturing approach similar to filament winding has been developed and is able to produce the Composite Material Marine Current Turbines (CMMCTs) that have significant advantages over traditional designs. This paper presents numerical results investigating the performance of ducted CMMCTs. The numerical approach was performed using CFD in a free stream of water with various hydrodynamic flow conditions. The investigation results provide an insight into the hydrodynamic design and operation of CMMCTs.

A novel manufacturing approach similar to filament winding is able to produce high-performance and light-weight composite wheels in a rapid, inexpensive way by utilizing commercially available winding machines. In this study, a numerical investigation of a diffuser-augmented composite wind turbine is evaluated with a conventional bare wind turbine by using FLUENT in conjunction with the GAMBIT meshing tool. The extracted torque and power are calculated and compared for these two modeling designs. The simulation results show that the extracted power of a diffuser-augmented turbine can be 5 times the power extracted by a bare turbine of the same turbine area. This analysis procedure provides an insight into the hydrodynamic design and operation of a diffuser-augmented wind turbine in order to shorten the design period and improve technical performance.