Hot Working Technology SHMP is a production center of heavy duty castings and forgings in east region of China. Since the establishment of the plant in 1950s, through several generations’ exploration, development and...Hot Working Technology SHMP is a production center of heavy duty castings and forgings in east region of China. Since the establishment of the plant in 1950s, through several generations’ exploration, development and innovation, SHMP now has been able to produce main castings and forgings for 300 MW展开更多
We investigate the subsurface heat exchange process in EGS （enhanced geothermal systems） with a previously developed novel model. This model treats the porous heat reservoir as an equivalent porous medium of a singl...We investigate the subsurface heat exchange process in EGS （enhanced geothermal systems） with a previously developed novel model. This model treats the porous heat reservoir as an equivalent porous medium of a single porosity. However, it considers local thermal non-equilibrium between solid rock matrix and fluid flowing in the factures and employs two energy conservation equations to describe heat transfer in the rock matrix and in the fractures, respectively, enabling the modeling and analyses of convective heat exchange in the heat reservoir. Another salient feature of this model is its capability of simulating the complete subsurface heat exchange process in EGS. The EGS subsurface geometry of interest physically consists of multiple domains： open channels for injection and production wells, the artificial heat reservoir, and the rocks enclosing the heat reservoir, while computationally we treat it as a single-domain of multiple sub-regions associated with different sets of characteristic properties （porosity and permeability, etc.）. This circumvents typical difficulties about matching boundary conditions between sub-domains in traditional multi-domain approaches and facilitates numerical implementation and simulation of the complete subsurface heat exchange process. This model is used to perform a comprehensive parametric study with respect to an imaginary doublet EGS. Effects of several parameters, including the permeability of heat reservoir, heat exchange coefficient in the heat reservoir, the specific area of fractures in the heat reservoir, and thermal compensation from surrounding rocks, on the heat extraction efficiency and EGS lifetime are analyzed.展开更多
The hot deformation characteristics of GH738 superalloy over the temperature range of 1000 °C to 1 200 °C and strain range of 0.01 s^-1 to 10.0 s^-1 under a strain of 1.0 s^-1 were investigated through hot c...The hot deformation characteristics of GH738 superalloy over the temperature range of 1000 °C to 1 200 °C and strain range of 0.01 s^-1 to 10.0 s^-1 under a strain of 1.0 s^-1 were investigated through hot compression tests with a Gleeble-1500 simulation machine. The flow stress reached peak value before flow softening occurred. The average apparent activation energy（Q） of GH738 was calculated to be 430 k J/mol, and the stress index（n） is approximately 4.08. The processing map was developed based on flow stress data and dynamic materials model（DMM）. The map shows a dynamic recrystallization（DRX） domain in 1 050 °C to 1150 °C and 0.01 s^-1 to 1.0 s^-1 strain rate range with a peak efficiency of 45%, which is considered to be the optimum region for hot working. Moreover, the materials undergo flow instability in the temperature range of 1000 °C to 1050 °C and strain range of 1.0 s^-1 to 10.0 s^-1, and adiabatic shear bands can be observed in this domain.展开更多
文摘Hot Working Technology SHMP is a production center of heavy duty castings and forgings in east region of China. Since the establishment of the plant in 1950s, through several generations’ exploration, development and innovation, SHMP now has been able to produce main castings and forgings for 300 MW
文摘We investigate the subsurface heat exchange process in EGS （enhanced geothermal systems） with a previously developed novel model. This model treats the porous heat reservoir as an equivalent porous medium of a single porosity. However, it considers local thermal non-equilibrium between solid rock matrix and fluid flowing in the factures and employs two energy conservation equations to describe heat transfer in the rock matrix and in the fractures, respectively, enabling the modeling and analyses of convective heat exchange in the heat reservoir. Another salient feature of this model is its capability of simulating the complete subsurface heat exchange process in EGS. The EGS subsurface geometry of interest physically consists of multiple domains： open channels for injection and production wells, the artificial heat reservoir, and the rocks enclosing the heat reservoir, while computationally we treat it as a single-domain of multiple sub-regions associated with different sets of characteristic properties （porosity and permeability, etc.）. This circumvents typical difficulties about matching boundary conditions between sub-domains in traditional multi-domain approaches and facilitates numerical implementation and simulation of the complete subsurface heat exchange process. This model is used to perform a comprehensive parametric study with respect to an imaginary doublet EGS. Effects of several parameters, including the permeability of heat reservoir, heat exchange coefficient in the heat reservoir, the specific area of fractures in the heat reservoir, and thermal compensation from surrounding rocks, on the heat extraction efficiency and EGS lifetime are analyzed.
基金Item Sponsored by National High Technology Research and Development Program(863 Program)of China(2012AA03A502)
文摘The hot deformation characteristics of GH738 superalloy over the temperature range of 1000 °C to 1 200 °C and strain range of 0.01 s^-1 to 10.0 s^-1 under a strain of 1.0 s^-1 were investigated through hot compression tests with a Gleeble-1500 simulation machine. The flow stress reached peak value before flow softening occurred. The average apparent activation energy（Q） of GH738 was calculated to be 430 k J/mol, and the stress index（n） is approximately 4.08. The processing map was developed based on flow stress data and dynamic materials model（DMM）. The map shows a dynamic recrystallization（DRX） domain in 1 050 °C to 1150 °C and 0.01 s^-1 to 1.0 s^-1 strain rate range with a peak efficiency of 45%, which is considered to be the optimum region for hot working. Moreover, the materials undergo flow instability in the temperature range of 1000 °C to 1050 °C and strain range of 1.0 s^-1 to 10.0 s^-1, and adiabatic shear bands can be observed in this domain.
