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The reciprocating engine has the maximum pressure and temperature in the cylinder, higher than that of the conventional gas turbines. When the gas engine is integrated with gas turbine instead of turbocharger, ETCS (the engine-turbo compound system) is composed. This paper defines the compound system with ERGT (the Engine Reheat Gas Turbine) and optimizes the engine operating condition. Natural gas firing steam/gas turbine combined cycle is selected as the standard system of thermal power plant. The higher TIT (Turbine Inlet Temperature) of gas turbine usually enables the higher power generation efficiency. This paper shows the effect of engine exhaust temperature on the cycle performance with no change of TIT and that the exhaust of 900°C increases the system power generation efficiency from 46 to 50% LHV (TIT 1 150°C) and 54 to 57% LHV (TIT 1 350°C), respectively.

For an enhancement of power generating system, the CH4/O2 fired gas turbine that is one kind of CBC (Closed Brayton Cycle) and the CH4/O2 fired steam turbine are proposed as a solution of high performance and non-CO2 emission into the environment of atmosphere. The combined plant of these two closed cycle systems results in the generating efficiency of 60.1% HHV at 1 350°C of firing temperature and 61.8% HHV at 1500°C. The CH4/O2 fired gas turbine can supplant a conventional open cycle gas turbine in a combined cycle power plant. On the contrary, the CH4/O2 fired steam turbine can be used with a conventional open cycle gas turbine. These two applications are expected as the modification of conventional combined cycle to achieve the reduction of CO2 emission or repowering.

In recent years, concern has been raised about developing a distributed energy system and the micro gas turbine and the fuel cell are used for it. Solid oxide fuel cell (SOFC) has a high electric generation efficiency and a high operating temperature (about 1000°C). It is easy to combine a gas turbine with the SOFC because the SOFC operating temperature matches the turbine inlet temperature (TIT). In this study, we proposed the multi stage type SOFC/GT combined system and compared the system performance of it with that of other traditional combined systems using the thermal efficiency and exergy evaluation. It is noted that the thermal efficiency of the 3-stage type SOFC/GT combined system can be reached more than 70% (HHV) at low pressure ratio.

In certain rotor systems, bending-torsion coupled resonance occurs when the rotational speed Ω (= 2π Ωrps) is equal to the sum/difference of the bending natural frequency ωb (= 2π fb) and torsional natural frequency ωθ(= 2πfθ). This coupling effect is due to an unbalance in the rotor. In order to clarify this phenomenon, an equation was derived for the motion of the bending-torsion coupled 2 DOF system, and this coupled resonance was verified by numerical simulations. In stability analyses of an undamped model, unstable rotational speed ranges were found to exist at about Ωrps = fb + fθ. The conditions for stability were also derived from an analysis of a damped model. In rotational simulations, bending-torsion coupled resonance vibration was found to occur at Ωrps = fb − fθ and fb + fθ. In addition, confirmation of this resonance phenomenon was shown by an experiment. When the rotor was excited in the horizontal direction at bending natural frequency, large torsional vibration appeared. On the other hand, when the rotor was excited by torsion at torsional natural frequency, large bending vibration appeared. Therefore, bending-torsion coupled resonance was confirmed.

The gas engine-gas turbine combined cycle was developed as the ETCS (Engine Turbo Compound System) that has a potential to be a future high performance combined cycle. The reciprocating engine operates with a maximum pressure and temperature in the cylinder, higher than that of the conventional gas turbines. When the gas engine is integrated with a gas turbine instead of a turbocharger, the concept of the ETCS with ERGT (Engine Reheat Gas Turbine) is available. In order to attain a better ETCS performance, a natural gas firing RGT (Regenerative Gas Turbine) was selected as the core gas turbine. For the system integration, the recuperator of RGT was exchanged for a gas engine. Focusing on the effect of engine exhaust temperature, we found that the ETCS cycle with ERGT has the potential to achieve a higher thermal efficiency than that of a re-generative cycle gas turbine with no change of TIT (Turbine Inlet Temperature). The engine exhaust temperature of 900°C increases the system power generation efficiency from 39% of RGT to 45% in ERGT (GT-Gas Engine) and up to 59% in ETCS (GT-Gas Engine-Steam Turbine) (TIT 1200°C).Copyright © 2007 by ASME

Air cooling blades are usually applied to gas turbines as a basic specification. This blade cooling air is almost 20% of compressor suction air and it means that a great deal of compression load is not converted effectively to turbine power generation. This paper proposes the CCM (Cascade Cooling Module) system of turbine blade air line and the consequent improvement of power generation, which is achieved by the reduction of cooling air consumption with effective use of recovered heat. With this technology, current gas turbines (TIT: turbine inlet temperature: 1350°C) can be up-rated to have a relative high efficiency increase. The increase ratio has a potential to be equivalent to that of 1500°C Class GT/CC against 1350°C Class. The CCM system is designed to enable the reduction of blade cooling air consumption by the low air temperature of 15°C instead of the usual 200–400°C. It causes the turbine operating air to increase at the constant suction air condition, which results in the enhancement of power and thermal efficiency. The CCM is installed in the cooling air line and is composed of three stage coolers: steam generator/fuel preheater stage, heat exchanger stage for hot water supplying and cooler stage with chilled water. The coolant (chilled water) for downstream cooler is produced by an absorption refrigerator operated by the hot water of the upstream heat exchanger. The proposed CCM system requires the modification of cooling air flow network in the gas turbine but produces the direct effect on performance enhancement. When the CCM system is applied to a 700MW Class CC (Combined Cycle) plant (GT TIT: 135°C Class), it is expected that there will be a 40–80MW increase in power and +2–5% relative increase in thermal efficiency.Copyright © 2006 by ASME

The reciprocating engine operates with a maximum pressure and temperature in its cylinders that is higher than that in conventional gas turbines. When a gas engine is integrated with a gas turbine instead of a turbocharger, it is an ETCS (Engine-Turbo Compound System). We have developed the concept of a compound system with ERGT (Engine Reheat Gas Turbine) and propose it as a system with potentially high thermal efficiency. A natural gas firing gas turbine combined cycle (CC) is selected as the standard system for a thermal power plant. A higher TIT (Turbine Inlet Temperature) of gas turbine usually enables higher power generation efficiency. Focusing on the effect of engine exhaust temperature, we found that the ETCS cycle with a ERGT has the potential to achieve higher thermal efficiency than that of a gas turbine combined cycle, with no change in TIT. An engine exhaust temperature of 1173K increases the system power generation efficiency from 46 to 50%LHV (TIT 1150°C) and 54 to 57%LHV (TIT 1350°C), respectively. The gas engine–gas turbine combined cycle has the potential to achieve a significant efficiency increase of +4.1%LHV (TIT 1150°C) and +2.8%LHV (TIT 1350°C), making it a promising system for future power plants. Efficiency is expected to be improved by +8.7% (TIT 1150°C) and +5.6% (TIT 1350°C), relatively.Copyright © 2005 by ASME

Today, the need to develop more efficient thermal power systems that emit less greenhouse effect gas has become a paramount importance. In line with this awareness, our research has leapt into such development that the combination of SOFC and Gas Turbine could generate power at extremely high efficiency. In this paper, we would like to present our concept of Inter Cooled Multistage SOFC-GT Hybrid Power System, developed to maximize fuel heat input to the system. We propose the combination of F-class GT (TIT 1350°C class) and 5 stage SOFC as the best for the hybrid power plant system and 77% (LHV base) is achieved at high pressure ratio.Copyright © 2003 by ASME

The Lie algebra gr of all infinitesimal automorphisms of a Siegel domain in terms of polynomial vector fields was investigated by Kaup, Matsushima and Ochiai [6]. It was proved in [6] that gr is a graded Lie algebra; gr = g-1 + g-1/2 + g0 + g1/2 + g1 and the Lie subalgebra ga of all infinitesimal affine automorphisms is given by the graded subalgebra; ga = g-1 + g-1/2 + g0. Nakajima [9] proved without the assumption of homogeneity that the non-affine parts g1/2 and g1 can be determined from the affine part ga.

The theory of classification of homogeneous bounded domains in the complex number space Cn has been developed mainly in the recent papers [10], [6], [3] and [7]. As a result, the classification is reduced to that of S-algebras due to Takeuchi [7] which correspond to irreducible Siegel domains of type I or type II (For the definition of irreducibility see § 1). On the other hand Pjateckii-Sapiro [5] found large classes of homogeneous Siegel domains obtained from classical self-dual cones. Even in lower-dimensional cases, however, there are still homogeneous Siegel domains which do not appear in his results.

The rates of absorption of pure sulfur dioxide into aqueous sodium bisulfite, sodium hydroxide, and sodium sulfite solutions with and without a surface active agent were measured at 25°C using a liquid jet column. For the sulfur dioxide-sodium hydroxide system, the rate of absorption into the solution without surface active agent was higher than that into the solution with surface active agent, indicating the existence of the interfacial turbulence. The absorption rates obtained for the present system under the conditions of no interfacial turbulence were in good agreement with the theoretical predictions based on the penetration theory.

Influences of microenvironment of various polyelectrolytes, i.e., ionene polymers and polyamine sulfones, on the photo- and/or thermal isomerization between the trans and cis forms of sodium m-(4-ethoxyphenylazo)benzene sulfonate (SEPS) were studied. 6,6-Ionene demonstrated larger enhancing effect on the cis–trans thermal isomerization than 3,3-ionene, which indicated that the micropolarity or the pH around the polymer is important. In the Arrhenius plots for both photo- and thermal isomerizations, deviations from the linearity were observed. In the former case, a sharp bend and the negative apparent activation energy were obtained at the high temperature. Furthermore, they were sensitively affected by the polyelectrolytes.

Let D be a convex domain in the n-dimensional real number space Rn, not containing any affine line and A(D) the group of all affine transformations of Rn leaving D invariant. If the group A(D) acts transitively on D, then the domain D is said to be homogeneous. From a homogeneous convex domain D in Rn, a homogeneous convex cone V = V(D) in Rn+1 = Rn × R is constructed as follows (cf. Vinberg [11]):which is called the cone fitted on the convex domain D.