INFLUENCE OF GAS-DYNAMIC TESTING RIG PIPELINES MATERIAL ON THEIR DYNAMIC CHARACTERISTICS

2021 ◽  
pp. 118-125
Author(s):  
А.В. Саврико ◽  
С.Н. Лымич ◽  
К.В. Кружаев ◽  
В.С. Левин ◽  
А.В. Москвичев
Keyword(s):  
Flow Rate ◽  
Dynamic Characteristics ◽  
Dynamic Testing ◽  
Analytical Calculation ◽  
Working Fluid ◽  
Factors Affecting ◽  
Pressure Losses ◽  
Steel Pipes ◽  
Gas Dynamic ◽  
Friction Pressure

Приведено исследование зависимости газодинамических характеристик стенда от применяемого материала трубопровода. Oсновополагающими факторами, влияющими на работоспособность стенда, являются выходные параметры - давление и расход рабочего тела, которые напрямую зависят от потерь давления на трение, создаваемого элементами стенда. Для оценки степени влияния материалов на потери стенда выбраны два вида труб: полипропиленовые и металлические. Аналитические расчёты потери давления рассматриваемых трубопроводов из различного материала показали, что трубопроводы из полипропилена предпочтительнее. Однако при проведении эксперимента получены противоположные данные, которые показали, что в полипропиленовых магистралях возможно присутствие значительного количества диафрагм: в местах пайки труб, образовавшихся в процессе изготовления. Именно этот факт способствует существенному повышению значений сопротивлений в полипропиленовых трубопроводах на 20 % по сравнению со стальными трубами, где диафрагмы отсутствуют. В результате проведения исследования был введен коэффициент, учитывающий влияние диафрагм полипропиленового трубопровода при аналитическом расчете на сопротивление. Для сохранения более точных снимаемых значений с газодинамических стендов целесообразнее использовать трубопроводы из металла, в которых рассчитать потери возможно с отклонениями до 3 % Here we give the study of the dependence of the gas-dynamic characteristics of the stand on the pipeline material used. The fundamental factors affecting the performance of the stand are the output parameters-the pressure and flow rate of the working fluid, which directly depend on the friction pressure losses created by the elements of the stand. To assess the degree of influence of materials on the losses of the stand, we selected two types of pipes: polypropylene and metal. Analytical calculations of the pressure loss of the considered pipelines made of various materials have shown that pipelines made of polypropylene are preferable. However, during the experiment, we obtained the opposite data, which showed that a significant number of diaphragms may be present in polypropylene pipelines: in the places of soldering of pipes formed during the manufacturing process. This fact contributes to a significant increase in the resistance values in polypropylene pipelines by 20 % compared to steel pipes, where there are no diaphragms. As a result of the study, we introduced a coefficient that takes into account the influence of polypropylene pipeline diaphragms in the analytical calculation of resistance. To preserve more accurate values taken from gas-dynamic stands, it is more expedient to use metal pipelines in which it is possible to calculate losses with deviations of up to 3 %

FEATURES OF GASDYNAMIC CALCULATION INTERNAL GAS NETWORKS WHEN APPLYING GAS-HYDROGEN MIXTURES

2017 ◽  
Author(s):  
Mariia Serediuk ◽  
Keyword(s):  
Hydrostatic Pressure ◽  
Natural Gas ◽  
Volume Fraction ◽  
Hydrogen Gas ◽  
Gas Mixture ◽  
Pressure Losses ◽  
Gas Networks ◽  
Gas Dynamic ◽  
Friction Pressure ◽  
Hydrogen Mixtures

The peculiarities of gas-dynamic calculations of internal gas networks when using gas-hydrogen mixtures with a volume fraction of up to 20 % of hydrogen instead of natural gas have been established. Analytical dependences are obtained, which make it possible to estimate the increase in friction pressure losses and hydrostatic pressure in internal gas pipelines at increased costs, which compensate for the decrease in the heat of combustion of the hydrogen-gas mixture.

Combined Cycle Gas Turbine (CCGT) with Freon Steam Turbine

2015 ◽  
Vol 792 ◽  
pp. 351-358
Author(s):  
Anton Kuryanov ◽  
Ivo Mõik ◽  
Oksana Grigoryeva
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Economic Efficiency ◽  
Dynamic Characteristics ◽  
Combined Cycle ◽  
Working Fluid ◽  
Gas Dynamic ◽  
Methodical Approach ◽  
Combined Cycle Plant

The article considers the prospect of a combined-cycle plant with freon as the working fluid of the steam turbine. Methodical approach to the study of such plants is expounded. For the option, CCGT with gas turbine M701G2 and use of freon R134a results of calculations of technical and economic efficiency, gas-dynamic characteristics, design-layout parameters are shown. The effectiveness of investments has been assessed.

Paper 12: Fluid Flow Losses in A.C. Generator Stator Ventilating Ducts

1967 ◽  
Vol 182 (4) ◽  
pp. 87-95
Author(s):  
N. J. Carew ◽  
D. H. Freeston
Keyword(s):  
Pressure Drop ◽  
Flow Distribution ◽  
Air Gap ◽  
Working Fluid ◽  
Factors Affecting ◽  
Pressure Losses ◽  
Flow Losses ◽  
Brief Assessment ◽  
Table Model ◽  
Generator Stator

This paper reports an experimental investigation into the ventilation characteristics of the air gap/radial duct combination in electrical machines. The problem is basically of the manifold type in which the machine air gap is compared to the supply duct and the radial ventilating ducts represent the branches. The factors affecting the pressure drop and flow distribution arising from the change in air direction from circumferential in the air gap to radial in the ventilating ducts are examined. First, the influence of slot wedge and duct spacer position, relative to the air gap, was observed in a qualitative manner using a water table model; the resulting flow patterns are illustrated. Second, the same duct configurations were tested in a model of a stator segment using air as the working fluid. The results of pressure drop and mass flow distribution are presented for variations in gap static and dynamic pressures together with curves showing the distribution of pressure losses along the ducts. Finally comparisons are made between model and full-scale measurements with a brief assessment of instrument problems.

scholarly journals Method for Predicting Choke Flow in Vaned Radial Diffusers Based on Thermodynamic and Gas Dynamic Criteria

1994 ◽  
Author(s):  
U. Seidel ◽  
M. Rautenberg
Keyword(s):  
Flow Rate ◽  
State Variables ◽  
Flow Conditions ◽  
Pressure Losses ◽  
Gas Dynamic ◽  
Wide Range ◽  
Method Of Solution ◽  
Mach Numbers ◽  
Dynamic Relationships ◽  
Experimental And Theoretical Studies

Conventional vaned diffusers have the disadvantage of extremely high total pressure losses in the region of choke, resulting from channel constrictions in the diffuser cascade. This effect is closely related to increasing impeller tip Mach numbers Mu,2 or increasing diffuser inlet flow Mach numbers. This aspect demands very special attention in diffuser design. On the basis of experimental and theoretical studies a hypothetical description of flow conditions within the diffusor was undertaken. The key feature of the working hypothesis is a one-dimensional loss model which is formulated in terms of thermodynamic and gas dynamic relationships. In conjunction with an appropriate application of the laws of conservation, this formulation leads to a method of solution for determining the aerodynamic conditions at the choke condition. Moreover, the method of analysis presented here is also applicable to a wide range of problems in fluid dynamics. In view of the fact that the position of the compressor choke flow rate is physically defined at the cascade inlet and the minimum cascade crossection, this work concentrates thematically on the formulation of the state variables at these locations. The method of analysis was illustrated by way of examples, and the theoretical approach was verified on the basis of experimentally determined flow conditions at choke flow rate.

Hydraulic model of a water cooling system in a chemical plant

1988 ◽  
Vol 53 (4) ◽  
pp. 788-806
Author(s):  
Miloslav Hošťálek ◽  
Jiří Výborný ◽  
František Madron
Keyword(s):  
Flow Rate ◽  
Cooling System ◽  
Cooling Water ◽  
Graph Algorithm ◽  
Automatic Generation ◽  
Hydraulic Calculation ◽  
Return Flow ◽  
Flow Rates ◽  
Pressure Losses ◽  
Controlled Flow

Steady state hydraulic calculation has been described of an extensive pipeline network based on a new graph algorithm for setting up and decomposition of balance equations of the model. The parameters of the model are characteristics of individual sections of the network (pumps, pipes, and heat exchangers with armatures). In case of sections with controlled flow rate (variable characteristic), or sections with measured flow rate, the flow rates are direct inputs. The interactions of the network with the surroundings are accounted for by appropriate sources and sinks of individual nodes. The result of the calculation is the knowledge of all flow rates and pressure losses in the network. Automatic generation of the model equations utilizes an efficient (vector) fixing of the network topology and predominantly logical, not numerical operations based on the graph theory. The calculation proper utilizes a modification of the model by the method of linearization of characteristics, while the properties of the modified set of equations permit further decrease of the requirements on the computer. The described approach is suitable for the solution of practical problems even on lower category personal computers. The calculations are illustrated on an example of a simple network with uncontrolled and controlled flow rates of cooling water while one of the sections of the network is also a gravitational return flow of the cooling water.

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 Improving Output Performance of a Resonant Piezoelectric Pump by Adding Proof Masses to a U-Shaped Piezoelectric Resonator

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 500
Author(s):  
Jian Chen ◽  
Wenzhi Gao ◽  
Changhai Liu ◽  
Liangguo He ◽  
Yishan Zeng
Keyword(s):  
Flow Rate ◽  
Maximum Flow ◽  
Working Fluid ◽  
Driving Voltage ◽  
Piezoelectric Resonator ◽  
Piezoelectric Pump ◽  
Compact Structure ◽  
Output Performance ◽  
Volume Efficiency ◽  
Working Efficiency

This study proposes the improvement of the output performance of a resonant piezoelectric pump by adding proof masses to the free ends of the prongs of a U-shaped piezoelectric resonator. Simulation analyses show that the out-of-phase resonant frequency of the developed resonator can be tuned more efficiently within a more compact structure to the optimal operating frequency of the check valves by adjusting the thickness of the proof masses, which ensures that both the resonator and the check valves can operate at the best condition in a piezoelectric pump. A separable prototype piezoelectric pump composed of the proposed resonator and two diaphragm pumps was designed and fabricated with outline dimensions of 30 mm × 37 mm × 54 mm. Experimental results demonstrate remarkable improvements in the output performance and working efficiency of the piezoelectric pump. With the working fluid of liquid water and under a sinusoidal driving voltage of 298.5 Vpp, the miniature pump can achieve the maximum flow rate of 2258.9 mL/min with the highest volume efficiency of 77.1% and power consumption of 2.12 W under zero backpressure at 311/312 Hz, and the highest backpressure of 157.3 kPa under zero flow rate at 383 Hz.

scholarly journals Investigation of acoustic and gas dynamic characteristics of strongly swirled turbulent jets

2018 ◽  
Vol 980 ◽  
pp. 012017
Author(s):  
S Yu Krasheninnikov ◽  
VP Maslov ◽  
AK Mironov ◽  
PD Toktaliev
Keyword(s):  
Dynamic Characteristics ◽  
Turbulent Jets ◽  
Gas Dynamic

A Parametric Examination of the Factors Affecting the Performance of a Diffusion Absorption Refrigeration System

2021 ◽  
pp. 1-38
Author(s):  
Noman Yousuf ◽  
Timothy Anderson ◽  
Roy Nates
Keyword(s):  
Waste Heat ◽  
Operating Conditions ◽  
Design Parameters ◽  
Working Fluid ◽  
Low Grade ◽  
Absorption Refrigeration ◽  
Factors Affecting ◽  
Thermally Driven ◽  
Mass Flowrate ◽  
Diffusion Absorption

Abstract Despite being identified nearly a century ago, the diffusion absorption refrigeration (DAR) cycle has received relatively little attention. One of the strongest attractions of the DAR cycle lies in the fact that it is thermally driven and does not require high value work. This makes it a prime candidate for harnessing low grade heat from solar collectors, or the waste heat from stationary generators, to produce cooling. However, to realize the benefits of the DAR cycle, there is a need to develop an improved understanding of how design parameters influence its performance. In this vein, this work developed a new parametric model that can be used to examine the performance of the DAR cycle for a range of operating conditions. The results showed that the cycle's performance was particularly sensitive to several factors: the rate of heat added and the temperature of the generator, the effectiveness of the gas and solution heat exchangers, the mass flowrate of the refrigerant and the type of the working fluid. It was shown that can deliver good performance at low generator temperatures if the refrigerant mass fraction in the strong solution is made as high as possible. Moreover, it was shown that a H2O-LiBr working pair could be useful for achieving cooling at low generator temperatures.

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