114 results about "Energy balance equation" patented technology

The invention discloses a method and a system for partitioning total output of a single shaft gas-steam combined cycle generating set. The method comprises the following steps: (a) establishing a mathematical model of a gas compressor, a combustion chamber and a gas turbine; (b) acquiring a real-time production parameter of the generating set; (c) calculating the power of the gas turbine and the consumed power of the gas compressor according to the results of the steps (a) and (b); (d) deducting the consumed power of the gas compressor from the generated power of the gas turbine to obtain the output of the gas turbine; (e) listing a material balance equation and an energy balance equation for a waste heat boiler; and (f) establishing a mathematical model of a steam turbine, listing a heat balance equation for the waste heat boiler, and calculating the output of the steam turbine through the mathematical model of the steam turbine. The method and the system can master the contributions of the gas turbine and the steam turbine to the total output of the set and the performance of each key part in real time so as to perform effective adjustment and control according to the actual conditions of the set.

The invention relates to a leaching rate prediction and optimization operation method in the wet metallurgical leaching process. The method comprises the following steps: predicting a leaching rate by an established mixing model and giving optimization operation instructions, wherein an integrative dynamic mechanism model of the leaching process is established, and a material balance equation and an energy balance equation are gradually established in the leaching process on the basis of the ore-leaching dynamic principle of the integrative dynamic mechanism model. The device comprises a leaching rate prediction and optimization operation system in the leaching process, a host computer, a PLC and a field sensing transmitting part which comprises a pH value detecting instrument, a temperature detecting instrument, a flow detecting instrument, and the like. With the technical scheme, the leaching process can be greatly improved, the production can be constantly kept in an optimal state, the consumption of raw materials and energy sources is reduced, the operation period of equipment is prolonged and the relation change between supply and demand on markets can be reflected in time.

A numerical procedure is disclosed to improve the prediction of heat fronts when simulating hot fluid injection in viscous hydrocarbon reservoirs. The mathematical model is composed of the conventional governing equations that describe multiphase fluid flow and energy balance. The reservoir geometry can be partitioned into a regular Cartesian grid or an irregular corner-point geometry grid. The numerical procedure uses the finite different (FD) method to solve the flow equations and the discontinuous Galerkin (DG) method to solve the energy balance equation. The proposed FD-DG method is an alternative to the traditional solution procedure that uses the FD method to solve both the flow and the energy equations. The traditional method has the deficiency that it may require excessive number of grid cells to achieve acceptable resolution of the heat fronts. The proposed FD-DG method significantly reduces numerical dispersion near discontinuities in the solution of the energy equation and therefore provides a better capture of the heat fronts. To obtain a desired accuracy in the energy equation solution, the FD-DG method can be orders of magnitude faster than the traditional method. The superiority of the FD-DG method is that it converges on coarser grids while the traditional method requires much finer grids.

The invention discloses a remote sensing retrieval method for moisture of farmland soil. The method is based on an energy-balance equation and TVDI, and provides a quantitative dry and wet edges determination method and an improved TVQI model-temperature vegetation quantitative index (TVQI). The method is characterized in that A) forming a vegetation index-ground temperature characteristic space based on a remote sensing image observation value, according to the surface energy-balance equation, obtaining a quantitative dry edge, wherein the quantitative dry edge is determined by two points of Tds and Tdv; B) obtaining the quantitative wet edge, wherein the quantitative wet edge is determined by two points of Tws and Twv; and C) according to the TVQ1 model, calculating a soil moisture estimate value. The method overcomes restriction of vegetation cover types in calculation of VI-Ts characteristic space, and remote sensing retrieval precision of soil moisture can be increased.

The invention relates to a soft sensing method for true temperature of pyrolysis mixed products at the outlet of an ethylene cracking furnace, comprising the following steps: firstly obtaining the furnace tube parameters of the cracking furnace; then obtaining the information of cracking raw material; then calculating the composition of pyrolysis products at the outlet of the cracking furnace; according to a cracking process model, including mass balance equation, momentum balance equation and energy balance equation, calculating the composition profiles of the pyrolysis products at the outlet of a radiant section; then calculating coking thickness in a cracking furnace tube; calculating coking thickness in a adiabatic segment furnace tube according to the contents of small molecule unsaturated hydrocarbon and aromatic hydrocarbon in the pyrolysis products and running time; and finally calculating the difference value of the temperature of a measurement and control point and the true temperature of pyrolysis mixed products so as to calculate the true temperature of pyrolysis mixed products at the outlet of the ethylene cracking furnace. Through the method, the true temperature of gas mixture of pyrolysis products at a particular moment of time can be dynamically calculated, and accurate model of the ethylene cracking furnace can be established, so that the method provides the basis for the simulation, optimization and control of cracking process.

The invention discloses an energy theory-based prediction method for stress of a TMB (tunnel boring machine) disk hob. The prediction method comprises the following steps: (1) determining the normal pushing vertical force FV, the tangential rolling force FR and the lateral force FS of the hob in a rock breaking process; (2) establishing a hob stress model in the rock breaking process; (3) establishing a rock strain model during the rock breaking process of the hob; (4) establishing an energy-balance equation for the hob and rock; (5) according to the established rock strain model, by setting the principal stress direction of the rock and the principal stress direction of the hob under a cylindrical coordinate to be corresponding, obtaining surface forces on a wedge-shaped surface when the hob breaks the rock, and predicting the stress of the TMB disk hob. Aiming at analysis and research status of all influence factors in the mechanical property of the existing TMB disk hob, the invention discloses the microcosmic energy theory-based novel prediction method for the stress of the hob; through the influence of the added rotation speed of the hob on the stress characteristics of the hob to in previous studies, a basis is provided for the design theory of a cutter with TBM boreability.

The invention relates to modeling and optimization methods for the wax-oil hydrogen cracking process. The modeling method includes the steps that according to an industrial hydrogen cracking device, design parameters and operating data which are required by modeling are determined, and a hydrogen cracking lumped partition method is determined, wherein the design parameters comprise lengths and diameters of all beds, and the operating data comprises the feeding flow, inlet-and-outlet temperatures of all the beds, the relative density and distillation range data of feeding and a product and theproduct yield; a hydrogen cracking reaction network, a reaction kinetic equation, a material balance equation and an energy balance equation are determined; a hydrogen cracking mechanism model is solved; based on actual industrial operating data, the hydrogen cracking lumped kinetic parameters are corrected. The modeling and optimization methods for the wax-oil hydrogen cracking process are wide in adaptation and can be used for simulating and optimizing hydrogen cracking industrial reactors with different reaction-bed number times and different product yield requirements.

The invention discloses a method for predicating the temperature of a photovoltaic cell through photo-thermal property coupling. The method includes the following steps that in combination with actual time and irradiance information provided by TMY data obtained through standard measurement, vertical equivalence is performed on incident light of the photovoltaic cell module, and based on an atmospheric dispersion longitudinal transmission model method, a vertical equivalence incident spectrum of a disperse wavelength is obtained; in combination with a crystal silicon layer texture structure and photo-thermal coupling properties of the anti-reflection process of an ARC layer, the wavelength dispersion absorption coefficient of each layer of the layered structure of the photovoltaic cell is calculated to obtained the flux of radiation absorbed by each layer of the structure; a layered structure energy balance equation of the photovoltaic cell is established, and a photovoltaic cell layered structure working temperature sequence corresponding to a time sequence is obtained through iterative calculation. On the basis of the existing function of predicating the output power of the photovoltaic cell, the function of predicating the working temperature of the photovoltaic cell module is further achieved, so that the precision of predicating the output power of the photovoltaic cell module is easily improved, and accordingly the output power of the photovoltaic cell module is accurately predicated.

The invention discloses a method for measuring hemispherical total emissivity and heat conductivity of a large temperature difference sample. The method comprises the following steps of: heating a belt-shaped conductor sample by electrifying under a vacuum environment, and arranging a plurality of thermocouple measuring points along the axial direction of the sample; forming a sample analysis region, and measuring to get the current value and the voltage value of the analysis region; dividing the sample into a plurality of infinitesimal control bodies along the axial direction, building a steady-state energy balance equation of the infinitesimal control bodies, and respectively expressing the hemispherical total emissivity and the heat conductivity as mathematical functions about temperature; performing multiple groups of steady-state measurement experiments under different steady-state temperature conditions to form a plurality of steady-state energy balance equations; calculating the temperature distribution of each infinitesimal control body under different steady states, and the total emissivity and the heat conductivity of each infinitesimal control body under different steady-state temperature conditions. According to the method disclosed by the invention, the problem that the hemispherical total emissivity of the large temperature difference conductor material sample of which the heat conductivity is unknown cannot be measured in the prior art.

The invention relates to a heat flow meter and a measuring method thereof. An incoming flow thermometer (2), an electric heater (4) and an inflow thermometer (5) are sequentially arranged on an inflow tube which enters heat-exchange equipment; a fluid is heated by the electric heater to differentiate the temperatures respectively measured by the incoming flow thermometer (2) and the inflow thermometer (5); and an integrator (8) is used for collecting the temperatures (T1, T2 and T3) of the fluid and electric power (W) to obtain heat energy released by the fluid in the heat-exchange equipment: (shown in the above formula), wherein C1-2 is average specific heat when the fluid is between T1 and T2, and C2-3 is average specific heat when the fluid is between T2 and T3. In the method, flow meters are replaced by thermometers, and the integrator is used for collecting the parameters of the incoming flow thermometer, the inflow thermometer and an outflow thermometer, so that the heat energy released by the fluid in the heat-exchange equipment can be obtained according to the energy-balance equations of the electric heater and the heat-exchange equipment. Furthermore the heat flow meter has the advantages of high measurement accuracy, simple structure and low cost.

The invention relates to a catalytic cracking reaction system process simulation optimization model and a solution method thereof. A novel model is a model based on Gupta and the like; in order to contribute to solving the model in process simulation software such as AspenPlusTM, a new form is provided for part of expressions in a material balance equation, an energy balance equation and a fluidized state computation model; and components or stream physical property calculation subprograms provided by the process simulation software are called in the model solution process, so that the simulation optimization work of the model is finished by the process simulation software, the model is convenient to apply to engineering and the calculation result is accurate.

The invention discloses a method for thermoelectric coupling analysis of a double-glass photovoltaic module. Firstly, a simplified engineering mathematic model of the photovoltaic module is obtained according to physical models such as a single diode of a photovoltaic battery, and a simulation model of the photovoltaic module is established. Secondly, a heat exchange manner of the double-glass photovoltaic module is analyzed according to structure characteristics, physical characteristics and optical characteristics of the double-glass photovoltaic module; according to an energy balance equation, a relation equation of temperature, power, convection and thermal radiation of the module is established; and a temperature physical equation of the module is obtained. Finally, a thermoelectric coupling simulation model is established in combination with the engineering mathematic model and the temperature physical equation of the module, so that the thermoelectric coupling analysis of performance of the double-glass photovoltaic module can be achieved. The method disclosed by the invention makes up deficiency of existing models in consideration of temperature influences generated during performance research of the double-glass module, effectively makes up vacancy in the field, facilitates the performance research of the double-glass photovoltaic assembly and also facilitates further marketization of the double-glass photovoltaic module.

The present invention discloses a dual-active bridge DC converter direct power control method based on energy closed loop, and is suitable for the field of large-power bidirectional direct current conversion. Aiming at the dynamic response problem of a bidirectional full-bridge direct current converter, on the basis of single phase-shifting control, according to an output energy balance equation,an output voltage Uout is sampled and then squared to construct an output capacitance energy closed loop, the size of a phase-shifting angle is obtained through the direct power based on the dual-active bridge direct current converter power transmission model to generate switching control signals so as to achieve rapid regulation of the output voltage of the dual-active bridge DC converter. The method provided by the invention can effectively improve the dynamic response speed of the output voltage when a load is suddenly changed, only needs to sample the output voltage, and is low in cost, not sensitive to model parameters and easy for design and engineering implementation.

The invention relates to a dynamic modeling method for syngas one-step dimethyl ether preparation. The method is a novel method for dynamical modeling for the syngas one-step dimethyl ether preparation and firstly shows that including heat loss into the energy conservation equation for performing iterative computation to judge whether the temperature in a reactor is reasonable so as to calculate the ingredients in the reaction according to atomic material conservation, reaction kinetics equation and energy conservation equation; when calculating, the temperature and the content of each ingredient in the syngas one-step dimethyl ether preparation reactor are assumed; the contents of the ingredients in the reactor are calculated through the material conservation equation and reaction kinetics equation, and then whether the assumed temperature is reasonable is determined through the energy conservation equation. According to the reactor-based dynamic modeling method for syngas one-step dimethyl ether preparation, a novel path is provided for the calculation of dynamic modeling for the dynamic modeling method for syngas one-step dimethyl ether preparation.