scholarly journals Effect of Suction Nozzle Pressure Drop on the Performance of an Ejector-Expansion Transcritical CO2 Refrigeration Cycle

Entropy ◽  
2014 ◽  
Vol 16 (8) ◽  
pp. 4309-4321 ◽  
Author(s):  
Zhenying Zhang ◽  
Lili Tian
Keyword(s):  
Pressure Drop ◽  
Refrigeration Cycle ◽  
Nozzle Pressure ◽  
Suction Nozzle

Heat Exchanger Shellside Pressure Drop: Comparison of Predictions With Experimental Data

1988 ◽  
Vol 110 (1) ◽  
pp. 68-76 ◽  
Author(s):  
R. S. Kistler ◽  
J. M. Chenoweth
Keyword(s):  
Experimental Data ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Flow Induced Vibration ◽  
Ongoing Research ◽  
Pressure Drops ◽  
Complementary Method ◽  
Nozzle Pressure

A unique set of heat exchanger shellside pressure drop experimental data has become available from experiments at Argonne National Laboratory as a part of an ongoing research program in flow-induced vibration. These data provide overall pressure drop for a number of typical industrial heat exchanger configurations in addition to incremental pressure drop measurements along the shellside path. The test program systematically varied the baffle spacing, the tubefield pattern, and nozzle size for a series of isothermal water tests for segmentally baffled bundles. Also recently a comprehensive method has been published in the Heat Exchanger Design Handbook (HEDH) for the prediction of bundle shellside pressure drops. A search of the literature failed to reveal a complementary method for predicting the shellside nozzle pressure losses. This paper compares the predicted with the measured data and validates the adequacy and limitations of the HEDH method for full bundles of plain tubes. It further applies an extension to the method for no-tubes-in-the-window bundles. Adjustments were indicated to improve the predictions for finned tubes and methods were developed to predict shellside nozzle pressure drops. Overall pressure drop predictions were within plus or minus 20 percent.

Performance optimization for an open-cycle gas turbine power plant with a refrigeration cycle for compressor inlet air cooling. Part 1: Thermodynamic modelling

2009 ◽  
Vol 223 (5) ◽  
pp. 505-513 ◽  
Author(s):  
L Chen ◽  
W Zhang ◽  
F Sun
Keyword(s):  
Power Plant ◽  
Pressure Drop ◽  
Power Output ◽  
Working Fluid ◽  
Air Cooling ◽  
Refrigeration Cycle ◽  
Mixing Chamber ◽  
Compressor Inlet ◽  
Gas Turbine Power Plant ◽  
Flow Resistances

A thermodynamic model of an open cycle gas turbine power plant with a refrigeration cycle for compressor inlet air cooling with pressure drop irreversibilities is established using finite-time thermodynamics in Part 1 of this article. The flow processes of the working fluid with the pressure drops of the working fluid and the size constraints of the real power plant are modelled. There are 12 flow resistances encountered by the working fluid stream for the cycle model. Three of these, the friction through the blades, vanes of the compressor, and the turbines, are related to the isentropic efficiencies. The remaining flow resistances are always present because of the changes in the flow cross-section at the mixing chamber inlet and outlet, the compressor inlet and outlet, the combustion chamber inlet and outlet, the heat exchanger inlet and outlet, and the turbine inlet and outlet. These resistances associated with the flow through various cross-sectional areas are derived as functions of the mixing chamber inlet relative pressure drop, and they control the air flowrate and the net power output. The analytical formulae about the power output, efficiency, and other coefficients are derived with the 12 pressure drop losses. The numerical examples show that the dimensionless power output reaches its maximum at the optimal value and that the dimensionless power output and the thermal efficiency reach their maximum values at the optimal values of the compressor fore-stages pressure ratio of the inverse Brayton cycle.

The Development of Performance Prediction Methods for an Automotive CO2 A/C Cycle

2011 ◽  
Vol 3 (2) ◽  
Author(s):  
Akira Kaneko ◽  
Masafumi Katsuta ◽  
Takahiro Oshiro ◽  
Sangchul Bae ◽  
Shunji Komatsu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Performance Prediction ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Refrigeration Cycle ◽  
Air Conditioning System ◽  
Lubricant Oil ◽  
C Cycle ◽  
Simulation Results

In previous research, we have been focusing on the performance of the each element heat transfer and hydraulic performance of refrigeration cycle. Experimental investigations have been repeated several times, and finally, we have substantial database including the effect of lubricant oil. Moreover, the maldistribution of two-phase in an evaporator can be also predicted from the experimental database. Under these circumstances, this study is intended to effectively put the construction of an automotive CO2 air conditioning system into practical design use through the simulation using the above-mentioned database. This paper describes the refrigeration cycle performance prediction of each element (e.g., an evaporator, a gas-cooler, and so on) by a simulation using substantial database and various available correlations proposed by us and several other researchers. In the performance prediction model of heat exchangers, local heat transfer and flow characteristics are considered and, in addition, the effects of lubricant oil on heat transfer and pressure drop are duly considered. The comparison is also made between simulation results and bench test results using a real automotive air conditioning system. Finally, the developed simulation method can predict the cooling capacity successfully within ±10% for A/C system simulation. By incorporating the lubricant oil effect, the simulation results are improved to ±5% and ±15% for the cooling capacity and pressure drop for evaporator simulation, respectively.

scholarly journals Effects of Nozzle Exit Position on Condenser Outlet Split Ejector-Based R600a Household Refrigeration Cycle

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5160
Author(s):  
Yongseok Jeon ◽  
Hoon Kim ◽  
Jae Hwan Ahn ◽  
Sanghoon Kim
Keyword(s):  
Pressure Drop ◽  
Internal Pressure ◽  
Nozzle Exit ◽  
Performance Characteristics ◽  
Coefficient Of Performance ◽  
Cycle Performance ◽  
Refrigeration Cycle ◽  
Refrigeration System ◽  
Entrainment Ratio ◽  
Ejector Cycle

The objective of this study is to investigate the performance characteristics of a small-sized R600a household refrigeration system that adopts a condenser outlet split (COS) ejector cycle under various operating and ejector geometry conditions. The coefficient of performance and pressure lifting ratio of the COS ejector cycle were analyzed and measured by varying the entrainment ratio, compressor speed, and nozzle exit position. The optimum nozzle exit position in the COS ejector cycle adopted to achieve the maximum cycle performance was proposed as a function of the compressor speed and entrainment ratio. The optimum nozzle exit position was 0 mm when the entrainment ratio and compressor speed were low, and it increased as the entrainment ratio and compressor speed increased owing to the associated internal pressure drop in the suction section.

scholarly journals Experimental Study on the Atomization of Plain Orifice Injector Under Uniform and Non-Uniform Cross Flowing Air Stream

1987 ◽  
Author(s):  
Yan Zhang ◽  
Jun Yong Zhu ◽  
Li Xin Wang ◽  
Ju Shan Chin
Keyword(s):  
Pressure Drop ◽  
Flow Velocity ◽  
Air Flow ◽  
Cross Flow ◽  
Orifice Diameter ◽  
Air Velocity ◽  
Air Stream ◽  
Nozzle Pressure ◽  
Large Orifice ◽  
Air Flow Velocity

The effects of three parameters: air velocity, nozzle pressure drop and injector orifice diameter, on the spray characteristics of a plain orifice injector under uniform and non-uniform cross flowing air stream have been studied experimentally. For uniform cross flowing air stream, the results show that the effects of these parameters are interrelated. The exponents of these terms in a correlation are not constants. Based on a very large amount of experimental data, the following correlation has been derived for Sauter Mean Diameter. SMD = 8.28 • 10 4 V ¯ a A • Δ P ¯ f B • d ¯ C where: A = −1.59 −0.0044ΔP̄f −0.01 d̄ B = −0.13 −0.025 d̄ +0.34 Ma C = 0.36 −0.55 Ma −0.0032ΔP̄f (Va ≤ 140 M/s ; ΔPf ≤ 11 Kg·f/cm2 ; d ≤ 2.5 mm) For small orifice diameters, the drop size distribution parameter, N (Rosin-Rammler distribution ), decreases until a minimum then increases with air velocity. For large orifice diameters, it decreases with air velocity. N always decreases with the increases of nozzle pressure drop or orifice diameter. For non-uniform cross flowing air stream, atomizations under four velocity profiles with same averaged velocity and with a velocity recess of same shape but at different radial positions have been tested. The atomization data were compared with that of uniform cross flowing air stream. Two types of comparison were made based on: a) the undisturbed velocity, b) the averaged velocity, equals to the velocity of uniform cross flowing air stream. For former situation the atomization for non-uniform cross flowing air stream tested is always poorer. The influence from the velocity recess will be maximum at certain nozzle pressure drop. The experimental evidence obtained has shown that cross flow atomization is a combination of pressure atomization (at low air flow velocity) and airblast atomization (at high air flow velocity).

The Development of Performance Prediction Methods for an Automotive CO2 Air Conditioning Cycle

2010 ◽  
Author(s):  
Masafumi Katsuta ◽  
Takahiro Oshiro ◽  
Akira Kaneko ◽  
Sangchul Bae ◽  
Shunji Komatsu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Data Base ◽  
Performance Prediction ◽  
Air Conditioning ◽  
Refrigeration Cycle ◽  
Air Conditioning System ◽  
Lubricant Oil ◽  
Simulation Results ◽  
Cooling Ability

In previous researches, we have been focusing on the performance of the each element heat transfer and hydraulic performance of refrigeration cycle. Experimental investigations have been repeated several times and, finally, we have substantial data base including the effect of lubricant oil. Moreover, the mal-distribution of two-phase in an evaporator can be also predicted from the experimental data base. Under these circumstances, this study is intended to effectively put the construction of an automotive CO2 air conditioning system into practical design use through the simulation using the above-mentioned data base. This paper describes the refrigeration cycle performance prediction of each element (e.g. an evaporator, a gas-cooler, and so on) by a simulation using substantial data base and various available correlations proposed by us and several other researchers. In the performance prediction model of heat exchangers, local heat transfer and flow characteristics are considered and in addition, the effects of lubricant oil on heat transfer and pressure drop are duly considered. The comparison is also made between simulation results and bench test results using a real automotive air conditioning system. Finally, the developed simulation method can predict the cooling ability successfully within ±5%. By incorporating the lubricant oil effect, the simulation results are improved to ±5% and ±15% for the cooling ability and pressure drop respectively.

Optimization of MCHX Using CFD and Refrigeration Cycle Simulator

2014 ◽  
Vol 984-985 ◽  
pp. 1163-1173
Author(s):  
M. Ezhilan ◽  
P. Seeni Kannan
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
High Heat ◽  
Refrigeration Cycle ◽  
Air Conditioner ◽  
High Heat Transfer ◽  
Fluidic Devices ◽  
High Heat Transfer Rate

Micro channel heat exchangers (MCHX) can be broadly classified as fluidic devices that employ channels of hydraulic diameter smaller than 1 mm. The present study focused on validate the better configuration parameters of louver fin used in MCHX for apply in residential air-conditioner condenser. The study has considered for three different louver angle case, two different louver lengths for better louver angle case and finally two different louver pitches for better louver angle and louver length case. The study indicates that the pressure drop will depends upon the louver angle and pitch. The louver angle i.e. 25deg provides reasonable pressure drop and high heat transfer rate. Thus by changing the length of louver can increase the pressure drop in MCHX. The case ie., 1.2mm louver length have more heat transfer rate. But when comparing to 1mm louver length case Net Heat Transfer rate is high. So the study further continued by having the louver length 1mm and changing the louver pitch. The louver pitch 0.8 and 1.2 has only considered for the study. The length of louver can decrease the pressure drop in MCHX. The variation of net heat transfer rate to changing the louver pitch indicating the importance of number of louver present in the MCHX. Thus the present study indicates the importance of configuration parameters for MCHX. The study also indicates that the increasing the louver length and angle will increase the net heat transfer rate. While increasing the louver pitch is inversely proportional to the net heat transfer rate of MCHX.

Pressure-Scaling of Pressure-Swirl Atomizer Cone Angles

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
D. R. Guildenbecher ◽  
R. R. Rachedi ◽  
P. E. Sojka
Keyword(s):  
Pressure Drop ◽  
Ambient Pressure ◽  
Cone Angle ◽  
Spray Angle ◽  
Subsequent Increase ◽  
A Value ◽  
Nozzle Pressure ◽  
Swirl Atomizer ◽  
Pressure Swirl ◽  
Pressure Swirl Atomizer

An experimental investigation was conducted to study the effects of increased ambient pressure (up to 6.89MPa) and increased nozzle pressure drop (up to 2.8MPa) on the cone angles for sprays produced by pressure-swirl atomizers having varying amounts of initial swirl. This study extends the classical results of DeCorso and Kemeny, (1957, “Effect of Ambient and Fuel Pressure on Nozzle Spray Angle,” ASME Transactions, 79(3), pp. 607–615). Shadow photography was used to measure cone angles at x∕D0=10, 20, 40, and 60. Our lower pressure results for atomizer swirl numbers of 0.50 and 0.25 are consistent with those of DeCorso and Kemeny, who observed a decrease in cone angle with an increase in nozzle pressure drop, ΔP, and ambient density, ρair, until a minimum cone angle was reached when ΔPρair1.6∼100MPa(kg∕m3)1.6 (equivalent to 200psi(lbm∕ft3)1.6). Results for atomizers having higher initial swirl do not match the DeCorso and Kemeny results as well, suggesting that their correlation be used with caution. Another key finding is that an increase in ΔPρair1.6 to a value of 600MPa(kg∕m3)1.6 leads to continued decrease in cone angle, but that a subsequent increase to 2000MPa(kg∕m3)1.6 has little effect on cone angle. Finally, there was little effect of nozzle pressure drop on cone angle, in contrast to findings of previous workers. These effects are hypothesized to be due to gas entrainment.

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