71 Process heating, power and incineration (energy applications in industry) Fat1 ue behaviour of the nickel-based superalloy IN716 at elevate c9temperature
Branco, C. M. and Byrne, J. Materials at High Temperatures, 1994, 12, (4), 261-267. The paper presents the fatigue crack propagation results obtained at 600°C from CT specimens of the nickel-based superalloy IN718 used in turbine discs of aeroengines. Firstly, the influence of the stress ratio on the fatigue crack growth rates was assessed for a baseline trapezoidal load waveform with a frequency of 0.25 Hz and a 1 s duration in each step. These results were then compared for three crack growth laws. The results of a preliminary study of dwell time at maximum load are also presented. 95103961 Focus on CHP Thomas, T. Gas Engng. Mgmnt., Mar. 1995, 35, 45-52. In Britain today combined heat and power schemes operate on more than 700 sites with a total output of 30OOMW. The government has set a target to increase combined heat and poweroutput in Britain to SOOOMW by the year 2000. Provides a listing of companies active in this sector and supplies mformation on their capabilities and current activities. 95163962 Fuels used for comblned-cycle power generatlon Mizoguchi, A. et al., (Assigned to) Mitsubishi Heavy Ind. Ltd.; Osaka Gas Co.Ltd., JAP. Pat. JP.O6,272,515, Sep. 1994. Describes the fuels used for gas turbines in power generation, which are low-b. p. distillation fractions obtained by pyrolysis of crude oil mixed with pulverized coal under pressure.
Future drlve: Electric vehicles and sustalnable transportatlon Sperling,D. Lisa Magnino, Island Press, 1718 Connecticut Ave., NW,
Suite 300, Washington, DC.20009, USA. . The author illustrates the adverse energy and environmental consequences of increased car travel and outlines strategies for creating an environmentally benign system of transportation based largely on electric propulsion.
Gas turblnes wlth sequentlal combustion for cogeneratlon of heat and power
Frutschi, H. U. ABB Review, 1995, (3), 4-9. The introduction of a new gas turbine generation based on sequential combustion will make combined cycle power facilities burning natural gas or oil an even more attractive proposition to operators of district heating schemes. Besides offering economic benefits, advanced cycle systems have less impact on the environment and help to conserve fossil fuels. The socalled ‘thermodynamic heating system’ has a special contribution to make in this area; in the vast majority of cases, it makes more sense to take heat from a large thermal power plant and transport it to an existing or projected district heating network than to build and operate a new district heating power station. A typical example, although not fossil-based, is the district heating scheme REFUNA in northern Switzerland. This is rated ,at about 70 MW,, and supplies heat at 120/70°C to a rural area. 95103965 Home Is where the CHP Is Simmonds, R. Elec. Rev., Feb. 1995, 228, (3), 18-21. Discusses how combined heat and power units of S-20kW would be technically suitable for more tha 250,000 sites in the UK in various sectors. Research by the Energy T f chnology Support Unit (ETSU) has led to a feasible demonstration prototype. Reports that many workers in this field believe that domestic CHP will soon be practicable.
In-cylinder measurement trlbulton In a L-head engine
Chou, T. and Patterson, D. J. Combustion & Flame, Apr. 1995, 101, (l), 45-57. The distribution of fuel-air mixtures in many L-head engines is not homogeneous. If the local mixture is too rich or too lean, then incomplete combustion occurs. This can play a major role in unburned hydrocarbon and carbon monoxide emissions, Fuel-air mixture distribution depends on incylinder swirl and turbulence, and is directly related to intake-manifold configuration, fuel-delivery-system design and combustion-chamber shape. Understanding the spatial mixture distribution may help improve the design of these aforementioned components. Consequently, a more complete combustion process may result, and emissions reduced.
lnterdlffuslon between the platlnum-modlfled alumlnlde coating FIT 22 and nickel-based single-crystal superalloy8 at 1000 and 1200%
Gobel, M. et al., Materials at High Temperatures, 1994, 12, (4), 301-309. The interdiffusion between the Pt-modified aluminide coating RT 22 and the single-crystal superalloys CMSX-6 and SRR 99 has been investigated at 1000 and 1200°C up to 1600 h of exposure time in air and vacuum. Both coating/substrate systems possess remarkable stability at lOOO’C, in air as well as in vacuum. It appears that the plate-like precipitates of intermetallies in the interdiffusion zone between coating and substrate act as a barrier layer for interdiffusion. Some inward diffusion of Pt and Al and outward diffusion of Ti occur at 1000°C.
Maxlmum obtalnable power of a Carnot combined power plant Wu, C. Heat Recovery Sys. CHP, May 1995, 15, (4), 351-355.
The paper analyses the maximum obtainable power of a combined endoreversible Carnot cycle by using heat transfer to simulate the rates of energy exchange between the combined cycle and its surroundings.
On knocking predlctlon In spark lgnltlon englnes 95103969 Moses, E. et al., Combustion & Flame, May 1995, 101, (3), 239-261. The paper presents a theoretical model for knocking prediction in spark ignitton engines (EI engines). The model mimics the combustion chamber by means of two zones - one in front and one behind the flame front. The latter is characterized by a one-dimensional temperature distribution which emerges due to the Mache effect. The heat transfer is accounted for. Hightemperature chemical reactions are described via a chemical kinetic mechanism composed in the present work by combining several already validated detailed mechanisms. Flame velocity predictions by the new mechanism are compared to experimental data. 96/639?6 The scale of heat dlstrlbutlon Hoogendoorn, P. and De Brabander, H. Gas (Netherlands), Apr. 1995, 115, (4). 42-44. (In Flemish) According to the Projectbureau WarmteKracht (the Co-generation Project Office), both large-scale and small-scale cogeneration applications in combination with heat distribution represent significant energy-saving instruments in built-up areas, even when high heat losses during distribution are taken into account. Furthermore, the Project Office states that heat distribution projects with a well-considered approach and strict financial preconditions have particularly great potential in blocks of flats built in the 1960s and new residential areas with sufficiently high population densities. Small-scale cogeneration applications can be adapted to meet medium-load electricity demands. 95lO3971 Slzlng up the case for combined heat and power Griffiths, R. The Resource, Jan.-FEb. 1995, 3, (l), 25-27. The paper discusses the economics of cogeneration in the UK. Explains two approaches taken for the sTzing of engines for cogeneration systems and notes that size optimisation can only be achieved through a process of iteration. Illustrates in a table the impact that plant sizing can have on the financial performance of CHP schemes.
95/63972 Studles on creep/stress rupture behavlour of superalloy 716 weldments used In gas turblne appllcatlons Radhakrishna, C. and Rao, K. P. Materials at High Temperatures, 1994, 12, (4), 323-327. Superalloy 718 in the solution-treated condition was welded autogenously by electron beam welding and gas tungsten arc welding processes. The weldments after suitable heat treatment were subjected to creep/stress rupture testing at 650°C and 690 MPa. The results showed that the Laves phase resulting in the weld metal is detrimental to the creep rupture life of weld metals when present with the continuous morphology found in gas tungsten arc welds. The lower amounts and discontinuous morphology of the Laves phase in electron beam weldments in combination with favourable grain orientation resulted in relatively better rupture properties for these weldments.
Thermodynamic and economic analysls of comblned cooling, heatlng and power plants
Vanoli, R. et al., Condiz, dell’Aria, Jan. 1995, 39, (150), 53-69. (In Italian) Provides a thermodynamic and economic analysis of some non-conventional plants designed to meet heating, cooling and electricity requirements. Considers cogeneration plants in combination with absorption and/or compression heat pumps directly driven by the prime mover or by self-produced electrical energy. Highlights the energy and cost saving potential of these plants, and gives examples of applications for hospitals, hotels and service sector users.
11 PROCESS HEATING, POWER AND INCINERATION Energy Applications 95103974
Condiz. dell’Aria, Feb. 1995, 39, (2), 171-175. (In Italian) The paper discusses the presence of air in steam distribution and heat exchange equipment.
96103976 Alumlnum melting furnaces Hilaire, C. Gaz d’aujourd’hui, Mar. 1995, 119, (3), 157-160. (In French) The efficiency of melting furnaces has improved steadily over the last fifteen years. A new type of gas-fired rapid melting furnace using product preheating by the products of combustion and a specific internal arrangement was developed by Thermco and Gaz de France. This new equipment is presented in this article.
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