Parameter study of Variation noise in outdoor of air conditioner

2021 ◽  
Vol 263 (4) ◽  
pp. 2822-2829
Author(s):  
Minkyu KIM ◽  
Byoungha Ahn ◽  
Simwon Chin
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
High Speed ◽  
Rapid Change ◽  
Volume Control ◽  
Parameter Study ◽  
Air Conditioner ◽  
Load Variations ◽  
Compressor Inlet ◽  
The Difference

In the outdoor unit of a room air conditioner, the main factors that made it possible to vary the ability of cooling and heating are the development of BLDC motors, advances in inverter technology, and the development of refrigerant volume control technology. The main reason for this change in cooling and heating capacity is that it is possible to change the RPS of compressors. As the range of the compressor's RPS expands, so does the range of response to load variations. This is mainly based on the capacity of the high-pressure refrigerant produced by the compressor. When the compressor rotates at high speed or low speed, the difference in noise occurs depending on the difference in rotational speed. Of course, fans and motors also contribute to noise fluctuations, but the overall governing factor is the greater contribution of refrigerant from compressors and compressors. The refrigerant flows into the cycle configured in the outdoor unit and varies in speed and flow rate depending on the amount of refrigerant. This results in vibration and noise appearing in the form of radiations, resonances, solid sounds, resonances, and so on. There are several factors that can cause vibration or noise changes depending on the flow velocity and flow rate. In this paper, we selected reactance of compressor motors, mufflers directly connected to compressor discharge ports and accumulator at compressor inlet where fluid vibrations occur the most. First of all, reactance of motor responds quickly to load fluctuations and has a large instantaneous torque to instantaneous load fluctuations. The muffler, which is directly connected to the compressor discharge port, is the first Cavity where high-pressure gas meets, and can evaluate the concentration of kinetic energy that generates noise and improve the collection center to reduce fluctuating noise. The Accumulator is the part with the lowest temperature of refrigerant gas entering the compressor, and the rapid change in the flow path causes the most fluid to generate vibration and radiation of the structure. For this reason, we select three elements first. In this paper, we specifically describe the background of selecting three elements of an air conditioning outdoor unit for the variability of noise over RPS changes. We demonstrate that these factors can review the feasibility of the experiment, explain the results of the analysis, and possibility of reduce the variation noise.

Analysis of Static Characteristics of Pressure Seal in Actual High Pressure Pump

2011 ◽  
Author(s):  
Isao Hagiya ◽  
Katsutoshi Kobayashi ◽  
Yoshimasa Chiba ◽  
Tetsuya Yoshida ◽  
Akira Arai
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
High Speed ◽  
Control Volume ◽  
Leakage Flow ◽  
High Pressure Pump ◽  
Flow Rates ◽  
Leakage Flow Rate ◽  
Rotor Dynamic ◽  
Pressure Seal

We predicted the leakage flow rates of a pressure seal in an actual high-pressure multistage pump. Since the pressure of the actual pump is higher than that of a model pump, accurate prediction of leakage flow rate and rotor dynamic forces for an actual pump is more difficult than that for a model pump. A non-contacting seal is used as a pressure seal to suppress leakage flow for high-pressure multistage pumps. When such pumps are operated at high speed, the fluid force acting on an eccentric rotor may cause vibration instability. For vibration stability analysis, we need to estimate static and dynamic characteristics of the pressure seals, i.e., leakage flow rate and rotor dynamic coefficients. We calculated the characteristics of the pressure seal based on Iwatsubo group’s method. The pressure seal we developed has labyrinth geometry consisting of grooves with different sizes. This method numerically calculates the characteristics of the grooved seal by using a three-control-volume model and a perturbation method. We compared the calculated and measured leakage flow rates. We found that the calculated results quantitatively agreed with the measured one in the actual pump and the characteristics of pressure and velocity for the seal with non-uniform-sized grooves were clarified.

scholarly journals Development of High-Efficiency, High-Speed and High-Pressure Ambient Temperature Filling System Using Pulse Volume Measurement

2019 ◽  
Vol 9 (12) ◽  
pp. 2491
Author(s):  
SeBu Oh ◽  
SeHoon Oh ◽  
ByeongRo Min
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
High Speed ◽  
High Efficiency ◽  
Response Speed ◽  
Volume Measurement ◽  
Economic Feasibility ◽  
Industrial Sectors ◽  
Filling System ◽  
Filling Time

Adjusting the filling pressure is essential to fit the final gas volume when charging a carbonated beverage with high pressure. However, in the previous mechanical carbonated ambient filling system, it was difficult to control and monitor the charging conditions such as pressure, temperature and flow rate. In this study, we have developed a high efficiency carbonated ambient filling system capable of high speed and high pressure filling, by using a pulse type electronic flow-meter. The response speed characteristics of the M(BC) and F(MH) series valves were investigated. LMS Imagine.Lab Amesim (Siemens PLM Software) was used to calculate the charging and discharging time of the system under a high CO2 gas pressure condition. The quantitative and precise charging system was implemented with the change of filling time and monitoring/controlling/correction of flow rate. Moreover, a dual controller of the high-speed pulse output was established and a high-speed data processing/flow rate charging algorithm was applied in the system. The filling variation of the system was in the range of ±3 gram(gr) (standard deviation 0.57). The developed system could be applied to improve the quality of goods and economic feasibility at various industrial sectors.

Design of a High-Speed Rotating Test Rig for Adaptive Seal Systems

2015 ◽  
Author(s):  
Laura S. Beermann ◽  
Corina Höfler ◽  
Hans-Jörg Bauer
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
High Speed ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Parameter Study ◽  
Test Rig ◽  
Swirl Chamber ◽  
Mass Flows ◽  
Gap Width

Gas turbine engines are subject to increased performance and improved efficiency, which leads to rising core temperatures with additional cooling needs. Reducing the parasitic leakage in the secondary flow system is important to meet the challenging requirements. New seal designs have to be tested and optimized at engine like conditions, like high pressure of up to 9 bar and surface speed of up to 280 m/s as well as an adjusted flow field. Flexible seal designs are an innovative approach to reduce leakage mass flows significantly. Axial and radial movements during transient operating conditions can be compensated easily, thus allowing a smaller gap width and minimizing rub and heat load. This paper describes the design and construction of a new rotating test rig facility. To the knowledge of the authors, this is the only test rig with an adjustable gap width and flow field in a high pressure and speed range. The facility is capable of up to 8 bar differential pressure across the seal and up to 4 bar back pressure. The high revolution engine facilitates a surface speed of up to 280 m/s. A traversable casing allows a quick change of the gap width during operation and simulates radial and axial rotor/stator movements in the engine. The seal movement as well as the resulting gap width are measured during operation to fully understand the seal behavior. An important feature of the new test rig is the continuously adjustable pre-swirl system. It has been designed to cover the different flow conditions in the real engine. Therefore, a RANS parameter study of the pre-swirl chamber has been conducted, which shows the adjustability of different pre-swirl ratios for constant and changing inlet mass flows.

Visual Observation and Analysis of Hydrodynamic Structure of Water Jet in Application to Jet Grouting

2007 ◽  
Author(s):  
Hiroshi Yoshida ◽  
Kennosuke Uemura ◽  
Kenji Yoshida ◽  
Isao Kataoka
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
High Speed ◽  
Visual Observation ◽  
Water Jet ◽  
Structure Of Water ◽  
Jet Grouting ◽  
Hydrodynamic Structure ◽  
Jet Velocity ◽  
Very High

Water jet is utilized in various industrial application such as cutting carious materials and soil. In particular, jet grouting for soil improvement is one of the most important application of water jet under high pressure and high liquid flow rate. Such technology is already in practical use in civil engineering. In order to improve the efficiency and performance of jet grouting, it is quite important to clarify the hydrodynamic structure of water jet under high pressure and high flow rate. However, basic researches on this subject are quite insufficient both experimentally and analytically. Water jet utilized in jet grouting is usually very high speed ( up to 500 m/s) two-phase dispersed flow. Therefore, it is quite difficult to make visual observation of such water jet using conventional optical methods. In the present work, the authors utilized high sensitive CCD camera with image intensifier of which gate speed is 10 ns. Using this optical device, the authors obtained still image of high speed water jet for the first time. Visual observation revealed that high speed water jet is composed of very fine droplets and has complicated structures such as swirl and cluster of droplets. Velocity of water jet was also measured using two consecutive images taken between 10 microsecond. Such direct measurement of jet velocity of high speed water jet has not been carried out so far. The result indicated that jet speed (droplet speed) is even very high even at the boundary of water jet. Measure water jet velocity was reasonably correlated with jet velocity at the exit of nozzle.

scholarly journals Investigation of parameters of leakage of toxic and explosive substances and gases under the action of high pressure from tanks of the special purpose during

2021 ◽  
pp. 49-53
Author(s):  
M. Semerak ◽  
T. Hlova ◽  
B. Hlova ◽  
O. Petruchenko
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
Gas Flow ◽  
Toxic Substances ◽  
Gas Leakage ◽  
Emergency Situations ◽  
Time Flow ◽  
Steel Tanks ◽  
The Difference ◽  
Cylindrical Tanks

Tanks for the storage of oil products and toxic substances in warehouses are the main ones. They can be in the form of separate tanks or a group of tanks. The most widespread are vertical steel tanks with a stationary roof that a placed in open areas. The tanks heat up, and the intensity of evaporation of the oil product increases in case of fire. If there is a permanent roof, the pressure in the tank will increase. If the capacity of the breathing valves is less than the intensity of evaporation then there is a risk of explosion. Explosions in the tank often lead to the separation of the bottom, and the side cylindrical surface and the roof fly away instantly, spilling oil on neighboring tanks and the territory of the tank’s park. Then the combustion area increases intensively. The destruction of the integrity of the tank, due to the separation of the bottom, contributes to temperature and power stresses, the value of which increases with increasing temperature of their heating and increasing pressure, respectively. The values of temperature stresses are added to the power stresses caused by pressure, and when the critical value is reached, destruction occurs. In the article by the method of mathematical modeling using the laws of thermodynamics and mechanics of liquids and gases, analytical dependences for research of parameters of leakage of toxic substances and gases at action of high pressure from capacities at their storage are received. Saint-Venant’s principle was used to model the gas flow rate process. The dependence of the duration of gas leakage from special purpose tanks at the change of the area of the emergency hole and the pressure drop is obtained. The obtained results allow determining the velocity and mass flow rate of the gas depending on the area of the hole, the time flow, and the difference of pressure. Therefore, the task of research the emergency situations of engineering cylindrical tanks under the influence of temperature and pressure, which leads to the spillage of toxic substances and gassiness is actual. The researches results are presented graphically.

Design and analysis of a synthetic jet actuator-based fluid atomization device

2017 ◽  
Vol 28 (17) ◽  
pp. 2307-2316 ◽  
Author(s):  
Paul Gilmore ◽  
Vishnu-Baba Sundaresan ◽  
Jeremy Seidt ◽  
Jarrod Smith
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
High Speed ◽  
Fluid Management ◽  
Synthetic Jet ◽  
System Level ◽  
Substrate Thickness ◽  
High Speed Imaging ◽  
Peak Displacement ◽  
Synthetic Jet Actuator

High-pressure nozzles and ultrasonic atomizers are the two most common devices used to generate sprays. Each of these has some disadvantages, such as controllability in high-pressure nozzles and fluid management challenges in ultrasonic devices. To overcome these limitations, a new atomization technology using a synthetic jet actuator was developed and is presented here. The work includes design and experimental analysis of both the stand-alone synthetic jet actuator and the synthetic jet-based atomization device. The synthetic jet actuator is designed using a model-based approach and characterized by measuring dynamic orifice pressure, diaphragm peak-to-peak displacement, flow rate, and power consumption. Orifice pressure reaches 296 Pa at a flow rate of 16 mL/s and 186 Pa at a flow rate of 37 mL/s for two possible synthetic jet actuator geometries, respectively. Piezoelectric diaphragm displacement reaches 50 µm with a brass substrate thickness of 0.20 mm. The synthetic jet-based atomization device is characterized with high-speed imaging and measurement of water atomization rate. It produces droplets with average sizes of 92–116 µm at maximum rates of 19–28 µL/s, depending on the geometry of the synthetic jet actuator. The outcomes of this work are principles for designing effective synthetic jet-based atomization devices, as well as system-level implementation concepts and control schemes.

Performance Characteristics of Spiral-Groove and Shrouded Rayleigh Step Profiles for High-Speed Noncontacting Gas Seals

1969 ◽  
Vol 91 (1) ◽  
pp. 60-68 ◽  
Author(s):  
H. S. Cheng ◽  
V. Castelli ◽  
C. Y. Chow
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Performance Characteristics ◽  
Spiral Groove ◽  
Typical Performance ◽  
The Difference ◽  
Gas Seals ◽  
Groove Seal ◽  
Film Characteristics ◽  
Film Profile

Current methods in gas lubrication have been used in this paper to analyze the gas-film characteristics in a high-speed, face-type gas seal. Detailed analyses are presented for two different surface geometries, the spiral-groove-orifice seal and the shrouded Rayleigh step seal. Results are presented in three parts. The first part shows the performance of a spiral-groove seal without the orifices, and also the difference in performance when the grooves are located at the high pressure, low pressure, or both sides. The second part gives typical performance of a nonparallel film profile for the spiral-groove-orifice seal as well as for the shrouded Rayleigh step seal. In the last part, a comparison is made between the two seal geometries on their tolerance to coning or dishing under a constant seal load.

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