Thermo-economic-environmental optimization of injection mass flow rate in the two-stage compression refrigeration cycle (Case study: Mobarakeh steel company in Isfahan, Iran)

The ½ cycle refrigeration system on LPG fueled vehicles has a significant cooling effect. However, the cooling is very dependent on the heat exchange process in the evaporator. Therefore, this paper analyses the deviation of the actual cooling curve from the ideal scenario carried out on a laboratory scale. The analytical method used is the calculation of the effectiveness of the evaporator, which compares the actual to the potential heat transfer capacity. The LPG flow rate was varied from 1-6 g/s, while the evaporation pressure ranged between 0.05, 0.10, and 0.15 MPa, which applied to compact type evaporators with dimensions of 262 ´ 200 mm, with a thickness of 65 mm. The research results confirm that the higher the LPG mass flow rate, the lower the heat transfer effectiveness. At the higher LPG mass flow rate, heat transfer occurs less optimally, due to incomplete evaporation of LPG in the evaporator.

Download Full-text

Simulation and Optimization of Municipal Solid Waste Combustion: A Case Study of a Fixed Bed Incinerator

Journal of Engineering Research and Reports ◽

10.9734/jerr/2020/v11i317060 ◽

2020 ◽

pp. 5-19

Author(s):

Arthur M. Omari ◽

John P. John ◽

Baraka Kichonge

Keyword(s):

Municipal Solid Waste ◽

Solid Waste ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Fixed Bed ◽

Small Scale ◽

Waste Incinerator ◽

Simulation And Optimization

In this study, a Computational Fluid Dynamics (CFD) technique was used to develop a model for the simulation and flow conditions of the incinerator. The CFD technique are based on subdividing the volume of interest, i.e., the combustion chamber (or other parts of the plant) into a grid of elementary volumes. The relevant equations of conservation (mass, momentum, energy) are then applied to each of those elements, after defining all inputs, outputs and boundary conditions. The resulting system is then integrated from start to finish, after introducing momentum, mass and heat transfer. The objective of the study was to evaluate and optimize the performance of locally available incinerators in Tanzania. The small scale municipal solid waste incinerator modelling was done by using a fluent solver. The case study of the existing incinerator at a Bagamoyo hospital in Tanzania was used as a model and the obtained values were compared with simulated results and other publications for validation. The design optimization using CFD techniques to predict the performance of incinerator showed the deviation of input air by 14%, the mass flow rate by 26.5%, the mass fraction of carbon dioxide by 10.4% and slight deviation of nitrogen dioxide and carbon monoxide. The study suggested removing the ash during the incineration process by using a moving grate mechanism to minimize the possibility of formation of NOX. The study found the maximum mass flow rate capacity of incinerator to be 68kg/h with input air A1 as 0.03639 kg/s, input air A2 as 0.03046 kg/s and input air A3 as 0.03409 kg/s. The findings indicated that as capacity is scaled up, the available momentum declines relative to the dimensions of the furnace.

Download Full-text

Bayesian Mass Averaging in Rigs and Engines

Journal of Turbomachinery ◽

10.1115/1.4053534 ◽

2022 ◽

pp. 1-15

Author(s):

Pranay Seshadri ◽

Andrew Duncan ◽

George Thorne

Keyword(s):

Random Field ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Gaussian Random Field ◽

Analytical Calculation ◽

Sampling Procedure ◽

Stagnation Pressure ◽

Pressure Measurements

Abstract This paper introduces the Bayesian mass average and details its computation. Owing to the complexity of flow in an engine and the limited instrumentation and the precision of the sensor apparatus used, it is difficult to rigorously calculate mass averages. Building upon related work, this paper views any thermodynamic quantity's spatial variation at an axial plane in an engine (or a rig) as a Gaussian random field. In cases where the mass flow rate is constant in the circumferential direction but can be expressed via a polynomial or spline radially, this paper presents an analytical calculation of the Bayesian mass average. In cases where the mass flow rate itself can be expressed as a Gaussian random field, a sampling procedure is presented to calculate the Bayesian mass average. Examples of the calculation of the Bayesian mass average for temperature are presented, including with a real engine case study where velocity profiles are inferred from stagnation pressure measurements.

Download Full-text

The influence of occupants’ body mass on carbon dioxide mass flow rate inside a university classroom – case study

International Journal of Environmental Health Research ◽

10.1080/09603123.2018.1483010 ◽

2018 ◽

Vol 28 (4) ◽

pp. 432-447 ◽

Cited By ~ 5

Author(s):

Peter Kapalo ◽

Florin Domnita ◽

Ciprian Bacotiu ◽

Martin Podolak

Keyword(s):

Carbon Dioxide ◽

Mass Flow Rate ◽

Body Mass ◽

Mass Flow ◽

Flow Rate

Download Full-text

Flow Dynamic Behaviors and Characteristics of Two-Stage Viscous Pump in Microchannels

ASME 2008 6th International Conference on Nanochannels, Microchannels, and Minichannels ◽

10.1115/icnmm2008-62245 ◽

2008 ◽

Author(s):

Jianfeng Lu ◽

Jing Ding

Keyword(s):

Reynolds Number ◽

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Small Distance ◽

Flow Dynamic ◽

Two Stage ◽

Dynamic Behaviors ◽

Viscous Pump ◽

Identical Type

The flow dynamic behaviors and characteristics of a two-stage viscous pump with two rotating cylinderes in microchannels were numerically studied by laminar model. At low Reynolds numbers, the dimensionless mass flow rate almost keeps constant for similar flow structure in the identical type of pump, and it also has little variation with different types of pump expect for the staggered pump with very small distance between different cylinders. As the Reynolds number increasing, the dimensionless mass flow rate drops because of the vortices evolution, and the distance between different cylinders significantly affects the flow dynamic process. For large distance, two steady vortices appear behind the cylinders, and the flow dynamics of aligned and staggered pump are very similar. For small distance, the flow rate of the staggered pump almost decreases with the distance rising, while the flow rate of the aligned pump has a maximum at a specific distance. Corresponding to the single-stage pump, the mass flow rate of two-stage pump is remarkably enhanced, and the enhanment ratio will increase as Reynolds number droping. Meanwhile, the driving power of two cylinders drops very slowly as the distance decreasing.

Download Full-text

A Methodology for Characterizing Representativeness Uncertainty in Performance Indicator Measurements of Power Generating Systems

Journal of Verification Validation and Uncertainty Quantification ◽

10.1115/1.4041687 ◽

2018 ◽

Vol 3 (2) ◽

Author(s):

U. Otgonbaatar ◽

E. Baglietto ◽

Y. Caffari ◽

N. E. Todreas ◽

G. Lenci

Keyword(s):

Mass Flow Rate ◽

Mass Flow ◽

Flow Rate ◽

Cfd Simulation ◽

Performance Indicator ◽

Statistical Significance ◽

Rate Measurement ◽

Flow Rate Measurement ◽

True Value

In this work, a general methodology and innovative framework to characterize and quantify representativeness uncertainty of performance indicator measurements of power generation systems is proposed. The representativeness uncertainty refers to the difference between a measurement value of a performance indicator quantity and its reference true value. It arises from the inherent variability of the quantity being measured. The main objectives of the methodology are to characterize and reduce the representativeness uncertainty by adopting numerical simulation in combination with experimental data and to improve the physical description of the measurement. The methodology is applied to an industrial case study for demonstration. The case study involves a computational fluid dynamics (CFD) simulation of an orifice plate-based mass flow rate measurement, using a commercially available package. Using the insight obtained from the CFD simulation, the representativeness uncertainty in mass flow rate measurement is quantified and the associated random uncertainties are comprehensively accounted for. Both parametric and nonparametric implementations of the methodology are illustrated. The case study also illustrates how the methodology is used to quantitatively test the level of statistical significance of the CFD simulation result after accounting for the relevant uncertainties.

Download Full-text