A Study On Adapted Similitude Modeling Method of Turboexpander with Different Gas Working Fluids

2021 ◽  
Author(s):  
Yiran Li ◽  
Xing Wang ◽  
Xuehui Zhang ◽  
Yangli Zhu ◽  
Wen Li ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Modeling Method ◽  
Working Fluid ◽  
Working Fluids ◽  
Shaft Power ◽  
Equivalent Mass ◽  
Special Working ◽  
Application Scope

Abstract The study on similitude modeling method of turboexpander with different working fluids is not only the key technical means and necessary method for the research and development of turboexpander with special working fluids, but also an effective way to further expand the application scope of turboexpander. In this paper, a new similitude modeling method (NSMM), which is based on dimensional analysis, actual characteristics of real gas and seven similitude criteria, is proposed. On the basis of modeling criterion p4, the new similitude relationship of turboexpander with different gas working fluids is obtained based on rotational speed, inlet total temperature, specific heat ratio and gas constant. Aiming at NSMM, the similitude modeling performance of turboexpander with air, methane, CO2 and helium is verified by using Computational Fluid Dynamics method. The results show that the modeling effects on aerodynamic performance are well predicted in a wide range including the design point (expansion ratio 2.9~5.0), and the errors of the total-to-total isentropic efficiency, relative equivalent mass flow rate, relative equivalent shaft power are less than 0.74%, 1.94% and 1.69%, respectively. Methane and CO2 have the best modeling performance, their errors of efficiency, relative equivalent mass flow rate and relative equivalent shaft power are all less than 0.5%; Furthermore, the NSMM also has pinpoint accuracy with the prediction of internal flow field, which provides a good idea for further research on special working fluid turboexpander and an approach to expand the application scope of turboexpanders.

The Performance of a Novel Solar Cooling and Power System with Different Working Fluids

2014 ◽  
Vol 672-674 ◽  
pp. 86-93 ◽  
Author(s):  
Huan Lei ◽  
Jin Fu Yang ◽  
Dong Jiang Han
Keyword(s):  
Power System ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Performance ◽  
Supply And Demand ◽  
Heat Transfer Fluid ◽  
Working Fluid ◽  
Cooling Power ◽  
Working Fluids

Due to serious environmental problems and energy supply and demand issues, solar energy as a clean and abundant energy gets more and more attention. This paper presented a novel cooling and power system combined with PTCs. The system performance analysis was conducted with four different organic working fluids. The impacts of organic Rankine cycle (ORC) evaporation temperature, ORC condensing temperature and heat transfer fluid (HTF) mass flow rate in evaporator on system thermal performance were analyzed. The results show that system with toluene as working fluid has the highest thermal and exergy efficiency, and D4 and MDM have the lowest. Different working fluids have different cooling power to electricity ratios. The HTF mass flow rate in evaporator has a significant effect on system thermal performance.

scholarly journals Modelling an unconventional closed-loop deep borehole heat exchanger (DBHE): sensitivity analysis on the Newberry volcanic setting

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Hannah R. Doran ◽  
Theo Renaud ◽  
Gioia Falcone ◽  
Lehua Pan ◽  
Patrick G. Verdin
Keyword(s):  
Sensitivity Analysis ◽  
Heat Exchanger ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Energy Flow ◽  
Closed Loop ◽  
Working Fluid ◽  
Valuable Insight ◽  
Deep Borehole

AbstractAlternative (unconventional) deep geothermal designs are needed to provide a secure and efficient geothermal energy supply. An in-depth sensitivity analysis was investigated considering a deep borehole closed-loop heat exchanger (DBHE) to overcome the current limitations of deep EGS. A T2Well/EOS1 model previously calibrated on an experimental DBHE in Hawaii was adapted to the current NWG 55-29 well at the Newberry volcano site in Central Oregon. A sensitivity analysis was carried out, including parameters such as the working fluid mass flow rate, the casing and cement thermal properties, and the wellbore radii dimensions. The results conclude the highest energy flow rate to be 1.5 MW, after an annulus radii increase and an imposed mass flow rate of 5 kg/s. At 3 kg/s, the DBHE yielded an energy flow rate a factor of 3.5 lower than the NWG 55-29 conventional design. Despite this loss, the sensitivity analysis allows an assessment of the key thermodynamics within the wellbore and provides a valuable insight into how heat is lost/gained throughout the system. This analysis was performed under the assumption of subcritical conditions, and could aid the development of unconventional designs within future EGS work like the Newberry Deep Drilling Project (NDDP). Requirements for further software development are briefly discussed, which would facilitate the modelling of unconventional geothermal wells in supercritical systems to support EGS projects that could extend to deeper depths.

scholarly journals Thermal Characteristics Analysis on Multi- Heat Pipe Induced Heat Exchanger

2019 ◽  
Vol 9 (2S2) ◽  
pp. 143-147 ◽  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Pipe ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Cold Water ◽  
Hot Water ◽  
Working Fluid ◽  
Physical Parameters

In this investigation of multi heat pipe induced in heat exchanger shows the developments in heat transfer is to improve the efficiency of heat exchangers. Water is used as a heat transfer fluid and acetone is used as a working fluid. Rotameter is set to measure the flow rate of cold water and hot water. To maintain the parameter as experimental setup. Then set the mass flow rate of hot water as 40 LPH, 60LPH, 80 LPH, 100LPH, 120 LPH and mass flow rate of cold water as 20 LPH, 30 LPH, 40 LPH, 50 LPH, and 60 LPH. Then 40 C, 45 ºC, 50 ºC, 55 C, 60 ºC are the temperatures of hot water at inlet are maintained. To find some various physical parameters of Qc , hc , Re ,, Pr , Rth. The maximum effectiveness of the investigation obtained from condition of Thi 60 C, Tci 32 C and 100 LPH mhi, 60 LPH mci the maximum effectiveness attained as 57.25. Then the mhi as 100 LPH, mci as 60 LPH and Thi at 40 C as 37.6%. It shows the effectiveness get increased about 34.3 to the maximum conditions.

Effects of Fe3O4/Water Nanofluid on the Efficiency of a Curved Pipe

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Milad Kelidari ◽  
Ali Jabari Moghadam
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Volume Concentration ◽  
Volume Fraction ◽  
Working Fluid ◽  
Radius Of Curvature ◽  
Dean Number ◽  
Curved Pipe ◽  
Overall Efficiency

Different-radius of curvature pipes are experimentally investigated using distilled water and Fe3O4–water nanofluid with two different values of the nanoparticle volume fraction as the working fluids. The mass flow rate is approximately varied from 0.2 to 0.7 kg/min (in the range of laminar flow); the wall heat flux is nearly kept constant. The experimental results reveal that utilizing the nanofluid increases the convection heat transfer coefficient and Nusselt number in comparison to water; these outcomes are also observed when the radius of curvature is decreased and/or the mass flow rate is increased (equivalently, a rise in Dean number). The resultant pressure gradient is, however, intensified by an increase in the volume concentration of nanoparticles and/or by a rise in Dean number. For any particular working fluid, there is an optimum mass flow rate, which maximizes the system efficiency. The overall efficiency can be introduced to include hydrodynamic as well as thermal characteristics of nanofluids in various geometrical conditions. For each radius of curvature, the same overall efficiency may be achieved for two magnitudes of nanofluid volume concentration.

scholarly journals Comparison of Swing and Tilting Check Valves Flowing Compressible Fluids

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 758
Author(s):  
Zhi-xin Gao ◽  
Ping Liu ◽  
Yang Yue ◽  
Jun-ye Li ◽  
Hui Wu
Keyword(s):  
Mach Number ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Check Valve ◽  
Small Mass ◽  
Working Fluid ◽  
Valve Disc ◽  
Valve Opening ◽  
The Difference

Although check valves have attracted a lot of attention, work has rarely been completed done when there is a compressible working fluid. In this paper, the swing check valve and the tilting check valve flowing high-temperature compressible water vapor are compared. The maximum Mach number under small valve openings, the dynamic opening time, and the hydrodynamic moment acting on the valve disc are chosen to evaluate the difference between the two types of check valves. Results show that the maximum Mach number increases with the decrease in the valve opening and the increase in the mass flow rate, and the Mach number and the pressure difference in the tilting check valve are higher. In the swing check valve, the hydrodynamic moment is higher and the valve opening time is shorter. Furthermore, the valve disc is more stable for the swing check valve, and there is a periodical oscillation of the valve disc in the tilting check valve under a small mass flow rate.

scholarly journals The Preliminary Design of Radial Inflow Turbines

1989 ◽  
Author(s):  
A. Whitfield
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
State Of The Art ◽  
Turbine Rotor ◽  
Working Fluid ◽  
Preliminary Design ◽  
Power Ratio ◽  
Mach Numbers ◽  
Absolute Dimensions

A procedure is described which develops the non-dimensional design of a radial inflow turbine rotor. The design is developed, for any specified non-dimensional power ratio, with the objective of minimising the inlet and discharge Mach numbers so that the passage losses are minimised. Initially state of the art efficiencies are assumed but are later modified through the specification of empirical losses. The resultant non-dimensional design can be transformed to absolute dimensions through the specification of the inlet stagnation conditions and the mass flow rate of the working fluid.

The Preliminary Design of Radial Inflow Turbines

1990 ◽  
Vol 112 (1) ◽  
pp. 50-57 ◽  
Author(s):  
A. Whitfield
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
State Of The Art ◽  
Turbine Rotor ◽  
Working Fluid ◽  
Preliminary Design ◽  
Power Ratio ◽  
Mach Numbers ◽  
Absolute Dimensions

A procedure is described that develops the nondimensional design of a radial inflow turbine rotor. The design is developed, for any specified nondimensional power ratio, with the objective of minimizing the inlet and discharge Mach numbers so that the passage losses are minimized. Initially state-of-the-art efficiencies are assumed, but these are later modified through the specification of empirical losses. The resultant nondimensional design can be transformed to absolute dimensions through the specification of the inlet stagnation conditions and the mass flow rate of the working fluid.

scholarly journals Application of modelling approaches of twin-screw compressors: thermodynamic investigation and reduced-order model identification

2021 ◽  
Vol 312 ◽  
pp. 05001
Author(s):  
Edoardo Di Mattia ◽  
Agostino Gambarotta ◽  
Mirko Morini ◽  
Costanza Saletti
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Pressure ◽  
Operating Conditions ◽  
Simplified Model ◽  
Computational Time ◽  
Discharge Temperature ◽  
Twin Screw ◽  
Shaft Power

Refrigeration is an essential part of the food chain. It is used in all stages of the chain, from industrial food processing to final consumption at home. In these processes, mechanical refrigeration technologies are employed, where compressors increase gas pressure from evaporation to condensation. In industrial refrigeration systems, twin-screw compressors represent the most widely used technology. A detailed mathematical model of a twin-screw compressor has been developed in Simulink® using differential equations for energy and mass balances to simulate the compression cycle that includes suction, compression and discharge phases. Gas pressure and enthalpy can be calculated as time functions during the cycle. However, the computational times obtained limit the possibility to extend the use of the model in the development of control strategies for the whole refrigeration plant in its real operating conditions. Therefore, the detailed model has been used to train a simplified model developed in Matlab®: the simulated mass flow rate, shaft power and the fluid discharge temperature have been employed to identify several geometrical and thermodynamic parameters of the simplified model. The latter relies on non-linear algebraic equations and, thus, requires a very short computational time. A limited performance dataset has been used to train the model, and a different dataset to test it: the results of the models have been compared, and small errors in mass flow rate, shaft power and fluid discharge temperature have been observed.

Dynamic Behavior and Off-Design Performance Analysis of Solar Driven ORC Using Scroll Expanders

2019 ◽  
Author(s):  
Ying Zhang ◽  
Arun Kumar Narasimhan ◽  
Mengjie Bai ◽  
Li Zhao ◽  
Shuai Deng ◽  
...  
Keyword(s):  
Experimental Data ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
System Level ◽  
Working Fluid ◽  
Small Scale ◽  
Solar Insolation ◽  
Design Performance ◽  
Fluid Mass

Abstract Solar driven ORC system is a possible solution for small-scale power generation. A scroll expander is considered due to its better suitability among other positive displacement expanders for small-scale power outputs. This work conducted a test of an ORC system with an expansion valve by varying the working fluid mass flow rate in two scenarios. A dynamic system-level model of ORC was developed and validated with experimental data. The validated model was used to predict the ORC performance considering off-design conditions of expander and solar insolation. The experimental data showed that pressures and temperatures exhibited the same trend as that of the working fluid mass flow rate, of which the evaporation pressure was the most sensitive to this variation. The simulation results are in good agreement with the experimental results. Results from the dynamic model showed that the ORC power output was underestimated by up to 54.7%, when off-design performance of expander was not considered. Considering the expander off-design performance and solar insolation, a highest thermal efficiency of 7.6% and an expander isentropic efficiency of 80.6% were achieved.

Condensation flow at the wet steam centrifugal turbine stage

2019 ◽  
Vol 234 (8) ◽  
pp. 1108-1121 ◽  
Author(s):  
Yaping Liu ◽  
Xuefei Du ◽  
Xuyang Shi ◽  
Diangui Huang
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Three Dimensional ◽  
Velocity Slip ◽  
Aerodynamic Characteristics ◽  
Nucleation Theory ◽  
Wet Steam ◽  
Flow Angle ◽  
Shaft Power

This paper investigates spontaneous condensation of wet steam in a centrifugal turbine by means of three-dimensional computational fluid dynamics. The flow field and aerodynamic characteristics of the wet steam in the centrifugal turbine are compared and analyzed by using the equilibrium steam and nonequilibrium steam models, respectively, where the latter applies the classical droplet nucleation theory and neglects velocity slip between the liquid phase and the gaseous phase. The state parameters of wet steam are described here based on the IAPWS’97 formulation. It is concluded that under the design condition, the mass flow rate, wetness fraction, and flow angle of the wet steam centrifugal turbine in the nonequilibrium steam model all change compared with the equilibrium steam model, with values of 4.4%, 0.5%, and 10.57%, respectively. Then the performance variation of the wet steam centrifugal turbine is analyzed under different steam conditions and different outlet back-pressure conditions. The results show that the change law of the mass flow rate, shaft power, and wetness fraction in the centrifugal turbine are basically identical in both models, and the mass flow rate, shaft power, wheel efficiency, and entropy loss coefficient of the centrifugal turbine in the nonequilibrium steam model are all higher than those in the equilibrium steam model, whereas the outlet wetness fraction is lower than that in the equilibrium steam model.

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