Experimental and Numerical Prediction of the Pressure Drop Reduction of Catalytic Converter under Various Mass Flow Rate of Exhaust Gas for a Naturally Aspirated Diesel Engine

2019 ◽  
Author(s):  
Kanchi Gopi Vinodh Kumar ◽  
Sundararaj Senthilkumar ◽  
Edison Rajasingh
Keyword(s):  
Diesel Engine ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Catalytic Converter ◽  
Numerical Prediction ◽  
Exhaust Gas

Research on Two-Phase Flow Instability in Evaporator of Refrigeration System

2010 ◽  
Author(s):  
Nan Liang ◽  
Changqing Tian ◽  
Shuangquan Shao
Keyword(s):  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Two Phase Flow ◽  
Density Wave ◽  
Phase Flow ◽  
Constant Mass ◽  
Refrigeration System ◽  
Two Phase

As one kind of fluid machinery related to the two-phase flow, the refrigeration system encounters more problems of instability. It is essential to ensure the stability of the refrigeration systems for the operation and efficiency. This paper presents the experimental investigation on the static and dynamic instability in an evaporator of refrigeration system. The static instability experiments showed that the oscillatory period and swing of the mixture-vapor transition point by observation with a camera through the transparent quartz glass tube at the outlet of the evaporator. The pressure drop versus mass flow rate curves of refrigerant two phase flow in the evaporator were obtained with a negative slope region in addition to two positive slope regions, thus making the flow rate a multi-valued function of the pressure drop. For dynamic instabilities in the evaporation process, three types of oscillations (density wave type, pressure drop type and thermal type) were observed at different mass flow rates and heat fluxes, which can be represented in the pressure drop versus mass flow rate curves. For the dynamic instabilities, density wave oscillations happen when the heat flux is high with the constant mass flow rate. Thermal oscillations happen when the heat flux is correspondingly low with constant mass flow rate. Though the refrigeration system do not have special tank, the accumulator and receiver provide enough compressible volume to induce the pressure drop oscillations. The representation and characteristic of each oscillation type were also analyzed in the paper.

scholarly journals Analytical and Experimental Investigation of a Plate Fin Heat Exchanger at Cryogenics Temperature

2021 ◽  
Vol 39 (4) ◽  
pp. 1225-1235
Author(s):  
Ajay K. Gupta ◽  
Manoj Kumar ◽  
Ranjit K. Sahoo ◽  
Sunil K. Sarangi
Keyword(s):  
Heat Exchanger ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Cryogenic Temperature ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Compact Size

Plate-fin heat exchangers provide a broad range of applications in many cryogenic industries for liquefaction and separation of gasses because of their excellent technical advantages such as high effectiveness, compact size, etc. Correlations are available for the design of a plate-fin heat exchanger, but experimental investigations are few at cryogenic temperature. In the present study, a cryogenic heat exchanger test setup has been designed and fabricated to investigate the performance of plate-fin heat exchanger at cryogenic temperature. Major parameters (Colburn factor, Friction factor, etc.) that affect the performance of plate-fin heat exchangers are provided concisely. The effect of mass flow rate and inlet temperature on the effectiveness and pressure drop of the heat exchanger are investigated. It is observed that with an increase in mass flow rate effectiveness and pressure drop increases. The present setup emphasis the systematic procedure to perform the experiment based on cryogenic operating conditions and represent its uncertainties level.

Effect of Mass Flow Rate on Dryer Room Radiator Pressure Drop and Heat Transfer

2016 ◽  
Vol 836 ◽  
pp. 102-108
Author(s):  
Mirmanto ◽  
Emmy Dyah Sulistyowati ◽  
I Ketut Okariawan
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Electrical Power ◽  
Maximum Temperature ◽  
Inlet Temperature ◽  
Mass Flow Rates ◽  
Room Model

In the rainy season, in tropical countries, to dry stuffs is difficult. Using electrical power or fossil energy is an expensive way. Therefore, it is wise to utilize heat waste. A device that can be used for this purpose is called radiator. The effect of mass flow rate on pressure drop and heat transfer for a dryer room radiator have been experimentally investigated. The room model size was 1000 mm x 1000 mm x 1000 mm made of plywood and the overall radiator dimension was 360 mm x 220 mm x 50 mm made of copper pipes with aluminium fins. Three mass flow rates were investigated namely 12.5 g/s, 14 g/s and 16.5 g/s. The water temperature at the entrance was increased gradually and then kept at 80°C. The maximum temperature reached in the dryer room was 50°C which was at the point just above the radiator. The effect of the mass flow rate on the room temperature was insignificant, while the effect on the pressure drop was significant. Moreover, the pressure drop decreased as the inlet temperature increased. In general, the radiator is recommended to be used as the heat source in a dryer room.

Design and Optimization of the Restrictor of a Race Car

2015 ◽  
Author(s):  
Prithvi Raj Kokkula ◽  
Shashank Bhojappa ◽  
Selin Arslan ◽  
Badih A. Jawad
Keyword(s):  
Fluid Dynamics ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Air Flow ◽  
Intake Manifold ◽  
Maximum Pressure ◽  
Cross Sectional ◽  
Formula Sae

Formula SAE is a student competition organized by SAE International. The team of students design, manufacture and race a car. Restrictions are imposed by the Formula SAE rules committee to restrict the air flow into the intake manifold by putting a single restrictor of 20 mm. This rule limits the maximum engine power by reducing the mass flow rate flowing to the engine. The pull is greater at higher rpms and the pressure created inside the cylinder is low. As the diameter of the flow path is reduced, the cross sectional area for flow reduces. For cars running at low rpm when the engine requires less air, the reduction in area is compensated by accelerated flow of air through the restrictor. Since this is for racing purpose cars here are designed to run at very high rpms where the flow at the throat section reach sonic velocities. Due to these restrictions the teams are challenged to come up with improved restrictor designs that allow maximum pressure drop across the restrictor’s inlet and outlet. The design considered for optimizing a flow restrictor is a venturi type having 20 mm restriction between the inlet and the outlet complying with the rules set by Formula SAE committee. The primary objective of this work is to optimize the flow restriction device that achieves maximum mass flow and minimum pull from the engine. This implies the pressure difference created due to the cylinder pressure and the atmospheric pressure at the inlet should be minimum. An optimum flow restrictor is designed by conducting analysis on various converging and diverging angles and coming up with an optimum value. Venturi type is a tubular pipe with varying diameter along its length, through which the fluid flows. Law of governing fluid dynamics states that the “Velocity of the fluid increases as it passes through the constriction to satisfy the principle of continuity”. An equation can be derived from the combination of Bernoulli’s equation and Continuity equation for the pressure drop due to venturi effect. [1]. A Computational Fluid Dynamics (CFD) tool is used to calculate the minimum pressure drop across the restrictor by running a series of analysis on various converging and diverging angles and calculating the pressure drop. As a result, an optimum air flow restrictor is achieved that maximizes the mass flow rate and minimizes the engine pull.

The Effects of Tip Clearance on Performance of a Heavy Duty Multi Stages Axial Turbine

2012 ◽  
Author(s):  
Mohammad Reza Shirzadi ◽  
Hossein Saeidi
Keyword(s):  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Large Scale ◽  
Tip Clearance ◽  
Heavy Duty ◽  
Penetration Length ◽  
Axial Turbine ◽  
Commercial Code

In this article aerodynamic effects of tip clearance on a heavy duty axial turbine are studied. Three different tip clearances are considered for each rotor. For simplicity, a simple tip profile is assumed and cooling air is not modeled. Aerodynamic behavior of all stages is studied in terms of polytropic efficiency, leakage mass flow, secondary and total losses, penetration length, and total mass flow rate for different pressure ratios. Also three well established correlations of tip clearance loss are compared with CFD results to obtain the best model for performance calculation of such a large-scale turbine. The steady states, viscous and compressible flow governing equations representing the flow field with k-epsilon turbulence model are solved using commercial code ANSYS CFX.12. Useful data are presented to predict the variation of efficiency of each individual rotor, as well as entire turbine, as a function of relative tip gap (k/h). This information may be useable in design and troubleshooting. According to the results, even though pressure drop in rear stages across tip gap is lower than pressure drop in front stages, leakage mass flow rate is considerably high for this LP stages. Consequently, tip clearance losses of rear stages have significant effect on the entire turbine efficiency.

Optimization of Supercritical CO2 Brayton Cycle for Simple Cycle Gas Turbines Exhaust Heat Recovery Using Genetic Algorithm

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Akshay Khadse ◽  
Lauren Blanchette ◽  
Jayanta Kapat ◽  
Subith Vasu ◽  
Jahed Hossain ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Supercritical Co2 ◽  
Heat Recovery ◽  
Brayton Cycle ◽  
Exhaust Gas ◽  
Exhaust Heat ◽  
Exhaust Heat Recovery

For the application of waste heat recovery (WHR), supercritical CO2 (S-CO2) Brayton power cycles offer significant suitable advantages such as compactness, low capital cost, and applicability to a broad range of heat source temperatures. The current study is focused on thermodynamic modeling and optimization of recuperated (RC) and recuperated recompression (RRC) configurations of S-CO2 Brayton cycles for exhaust heat recovery from a next generation heavy duty simple cycle gas turbine using genetic algorithm (GA). This nongradient based algorithm yields a simultaneous optimization of key S-CO2 Brayton cycle decision variables such as turbine inlet temperature, pinch point temperature difference, compressor pressure ratio, and mass flow rate of CO2. The main goal of the optimization is to maximize power out of the exhaust stream which makes it single objective optimization. The optimization is based on thermodynamic analysis with suitable practical assumptions which can be varied according to the need of user. The optimal cycle design points are presented for both RC and RRC configurations and comparison of net power output is established for WHR. For the chosen exhaust gas mass flow rate, RRC cycle yields more power output than RC cycle. The main conclusion drawn from the current study is that the choice of best cycle for WHR actually depends heavily on mass flow rate of the exhaust gas. Further, the economic analysis of the more power producing RRC cycle is performed and cost comparison between the optimized RRC cycle and steam Rankine bottoming cycle is presented.

Thermal and Hydraulic Performances of Porous Microchannel Heat Sink using Nanofluids

2021 ◽  
pp. 1-32
Author(s):  
Zahir Uddin Ahmed ◽  
Md. Roni Raihan ◽  
Omidreza Ghaffari ◽  
Muhammad Ikhlaq
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Friction Factor ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Sink ◽  
Hydraulic Performance ◽  
Microchannel Heat Sink ◽  
Nanoparticle Concentration

Abstract Microchannel heat sink is an effective method in compact and faster heat transfer applications. This paper numerically investigates thermal and hydraulic characteristics of a porous microchannel heat sink (PMHS) using various nanofluids. The effect of porosity, inlet velocity and nanoparticle concentration on thermal-hydraulic performance is systematically examined. The result shows a significant temperature increase (40°C) of the coolant in the porous zone. The pressure drop reduces by 35% for γ = 0.32 compared to the non-porous counterpart, and this reduction of pressure significantly continues when γ further increases. The pressure drop with win is linear for PMHS with nanofluids, and the change in pressure drop is steeper for nanofluids compared to their base fluids. The average heat transfer coefficients increases about 2.5 times for PMHS, and a further increase of 6% in is predicted with the addition of nanoparticle. The average Nusselt number increases non-linearly with Re for PMHS. The friction factor reduces by 50% when γ increases from 0.32 to 0.60, and the effect of nanofluid on friction factor is insignificant beyond the mass flow rate of 0.0004 kg/s. Whilst Cu and CuO nanoparticles help to dissipate the larger amount of heat from the microchannel, Al2O3 nanoparticle appears to have a detrimental effect on heat transfer. The thermal-hydraulic performance factor strongly depends on the nanoparticles, and it slightly decreases with the mass flow rate. The increase of nanoparticle concentration, in general, enhances both h and ΔP linearly for the range considered.

Experimental Research on Pulsating Two-Phase Flow Pressure Drop Characteristics in Horizontal Rectangular Channel

2014 ◽  
Author(s):  
Siqi Zhang ◽  
Puzhen Gao
Keyword(s):  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Two Phase Flow ◽  
Rectangular Channel ◽  
Phase Flow ◽  
Two Phase ◽  
Mean Values ◽  
Water Mass Flow Rate

In spite of most previous studies since 1970, the theory of pulsating pipe flows supported by experimental investigations has not yet completed in comparison with the well-defined theory of steady pipe flows. Therefore, it seems that there is much to be done about experimental research in this field. In order to determine the resistance characteristics of two-phase flow under pulsatile conditions, an experimental investigation on two-phase flow with periodically fluctuating flow rates in a narrow rectangular channel is carried out. A frequency inverter is used to obtain experimental conditions with different fluctuating frequencies, amplitudes and mean values of water mass flow rate. After obtaining experimental results, comparisons between experimental frictional pressure drop values and theoretical calculations have been done. Two-phase flow on pulsating conditions is far more complicated than that on steady conditions because pulsating flow is composed of two parts: a steady component and a superimposed periodical time varying component called oscillation. In this paper, the influence of different fluctuating frequencies, amplitudes and mean values of liquid and gas mass flow rate on two-phase flow pressure drop characteristics is also discussed. The results show that the total pressure drop and water mass flow rate change with the same fluctuating period except for a phase difference. The phase lag also changes with the fluctuating frequencies and amplitude. The accelerating pressure drop changes dramatically in a fluctuating period, especially at the end of acceleration. Also, the time when the acceleration pressure drop has its maximum value lags the time when the acceleration reaches its peak, mainly because of the inertial of the fluid.

Feasibility Study on Dehydrogenation of LOHC Using Excess Exhaust Heat From a Hydrogen Fueled Micro Gas Turbine

2015 ◽  
Author(s):  
Balbina Hampel ◽  
Stefan Bauer ◽  
Norbert Heublein ◽  
Christoph Hirsch ◽  
Thomas Sattelmayer
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Energy Supply ◽  
Excess Energy ◽  
Exhaust Gas ◽  
Distributed Energy ◽  
Micro Gas Turbine ◽  
Exhaust Heat

In recent years, renewable energy technologies have received increasing attention. However, the constant availability of renewable energies is not predictable, so that technologies for excess energy storage become increasingly important. One possibility for the technical implementation of such a storage technology is to bind hydrogen, produced using this excess energy, to liquid organic compounds, so-called Liquid Organic Hydrogen Carriers (LOHC), where hydrogen is bound to a H2-lean LOHC molecule in an exothermal hydrogenation reaction. The dehydrogenation process releases the stored hydrogen in an endothermal reaction. This technology offers advantages such as storage and transport safety, along with the high energy density. LOHC systems can assist in the realization of future distributed energy supply networks, as well. Micro gas turbines (MGT) play an important role in distributed energy supply, so that the coupling of a hydrogen fueled MGT with a reactor for the dehydrogenation process is a desirable achievement. In such a combined system, the excess exhaust enthalpy can be used to maintain the endothermal dehydrogenation reaction without affecting the overall efficiency of the gas turbine. This paper investigates the feasibility of a direct coupling between a hydrogen fueled recuperated micro gas turbine and the dehydrogenation process using the excess exhaust heat. For this purpose, a numerical simulation based on energy balances and thermodynamic equilibrium is implemented to model the process. Primary criteria for the evaluation of the process feasibility are the MGTs exhaust gas temperature, the exhaust gas mass flow rate, and the LOHC mass flow rate through the dehydrogenation unit. These three parameters specify the mass flow rate of LOHC, which can be dehydrogenated and thus, the mass flow rate of released hydrogen. Using the implemented numerical model, the suitability of two different LOHCs, N-Ethylcarbazole and an industrial heat transfer oil is investigated at two different pressure levels with respect to thermodynamic feasibility and process efficiency. The results show that the usable excess enthalpy in the exhaust gas of the investigated Turbec T100 MGT is sufficient to release enough hydrogen for re-use as fuel in the micro turbine process for three of the four investigated cases.

Sign in / Sign up

Export Citation Format

Share Document