Rotary compressors have shown to have a good mechanical performance with quieter and smoother operation, thus are widely used in many applications. However, the critical factors affecting the overall efficiency of the compressors are mainly the mechanical losses. Friction losses in rotary compressors do not only reduce the mechanical efficiency, but also reduce the reliability and life-span of the compressor, (Teh and Ooi, 2009c).
In most of the rotary compressors, sliding components usually possess high relative velocities hence high friction which limits their mechanical performance. For example, friction analysis of a rolling piston compressor, (Matsuzaka and Nagatomo, 1982; Ozu and Itami, 1981; Yanagisawa and Shimizu, 1985a), has shown that high friction is generated between the rolling piston and the eccentric rotor.Matsuzaka and Nagatomo (1982) have improved the mechanical performance of the rolling piston rotary compressor by modifying the shape of the rolling piston and the lubrication system. As a result, the compression efficiency was increased to 94%, while the overall compressor efficiency obtained was 74%. Similarly in the scroll compressor.Hayano et al. (1988) have found that there was a significant friction loss between the fixed scroll and the rotating scroll.
In the rotary vane compressor, Kruse (1982) and Ma et al. (2004) have reported that large friction losses occur at the contacts between the vane tips and the stationary cylinder and as well as that between the vane sides and the vane slots on the rotor which lead to a poor mechanical efficiency and a limited use of the compressor. In comparison with a rotary vane compressor, Hua et al. (2008) have recently shown that a reduction of 54.8% in the friction po...
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...Refrigeration 32, 945-952.
Teh, Y.L., Ooi, K.T., 2009c. Theoretical study of a novel refrigeration compressor – Part I: Design of the revolving vane (RV) compressor and its frictional losses. Int. J. Refrigeration 32, 1092-1102.
Xiuling, Y., Zhiming, C., Zhen, F., 1992. Calculating model and experimental investigation of gas leakage, In: Proceedings of Purdue Compressor Technology Conference, pp. 1249-1255.
Yanagisawa, T., Shimizu, T., 1985a. Friction losses in rolling piston type rotary compressor. III. Int. J. Refrigeration 8 (3), 159–165.
Yanagisawa, T., Shimizu, T., 1985b. Leakage losses with a rolling piston type rotary compressor. I. Radial clearance on the rolling piston. Int. J. Refrigeration 8, 75-84.
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The aim of this experiment is to find out how much gas is given off by
Roller screws are accustomed remodel rotary movement into linear movement and the other way around. The bearing components are threaded rollers positioned between the screw and therefore the nut. The massive variety of contact points permits roller screws to support terribly high loads. The roller screw is comparable to the ball screw with the distinction that the load transfer components are threaded rollers. When put next to standard ball screws, have the subsequent advantages: the most advantage of roller screws is that they need an outsized variety of contact points to support the load with higher permissible static and dynamic load capability. Due to the larger variety of contact points the bearing perform is ensured by uniform spreading of load over the threaded rollers rather than balls just in case of ball screws. It's higher mechanics and dynamics in operating condition, generates less vibration and lower noise. The transmission exactitude of PRS is higher and may add a lot of more durable condition. Because to these compensation, a lot of analysis on roller screw has been administrated, and therefore the roller screw has been utilized in the medical, aerospace, military, assembly, Food and drink, Plastics, textiles and machine tools industries.
Aim: - An experiment on how a volume of nitrogen gas is affected by the pressure exerted on it.
Since the inception of pressurized systems to produce and transmit energy, it has been a constant goal to find safe, dependable means of relieving pressure. The simple, inexpensive, spring loaded relief valves has been manufactured for over a hundred and fifty years, performing its job with varying degrees of reliability over that time period.
and cause of the leak. If a leakage is determine, this will make the vehicle not
9. Tsung-Chih Wu, Chi-Hsiang Chen, Chin-Chung Li “Journal of Loss Prevention in the Process Industries,” http://www.sciencedirect.com/science/article/pii/S0950423007001362, 2008.
This chart shows the relationship between the fanning friction factor and the Reynolds number over a wide range of flow rates, from which the roughness parameter (e/D) for the piping system can be estimated.
The factors for exponential growth for air-conditioning are the HVAC Market, energy, environment, communication, societal, political, preparing for the future, looking ahead, and the conclusion. Buildings of the U.S. use approximately 35% of the nation’s precise total of energy consumption. The worth of shipments by U.S. HVAC manufacturers was over $28 billion of 1996. Since there are 52,000 CHC chillers needed to be replaced among the U.S., there’s a large opportunity for new chillers, new technology for the HVAC industry. The ozone depletion is an international issue in which is currently being resolved. The 3rd world countries are still allowed to manufacture CFC’s. Illegal imports of CFC’S to the U.S. is a consistent concern. Many illegal imports are virgin CFC’s. Those whom have a political overtones are specifically the ones whom create a protectionism of local commerce, having a negative impact on those inside and out of the country.
Saravanamutto, H. I. H., Rogers, G. F. C., Cohen, H., & Straznicky, P. V. (2009). Gas turbine theory (6th ed.). London, UK: Prentice Hall.
Knowing the information given in my introduction, I can hypothesise on two things. 1) The more paperclips there are, the greater the acceleration will be. 2) The shorter the rotor length is, the smaller the resistance will be.
Next Dalton’s law of partial pressure is used. The mixture of gas in the graduated cylinder was filled with two things: water vapor and air. Using the Dalton’s law, it can be concluded that the total pressure is equal to the pressure of air and the pressure of water vapor added together. This is an endothermic reaction which means that it absorbs heat, and when a reaction gains heat, it is repres...
... temperature of 112 0C also and a pressure 2.5 bar. Cooling water is used to condense the vapor exiting column. Remaining methane and hydrogen are separated in reflux drum where the vapor stream is combined with other gases streams. The overhead of first and second separator are combined to form fuel gas. The liquid stream exiting in the bottoms of the reflux drum is pumped at pressure of 3.3 bar for discharging pressure. The pump stream is separated in two streams. One stream is to feed to tray one of the column and the other one stream is cooled down to 38 0C in heat exchanger. Then, the cooled product stream is sent to storage.
Process ab: The vapour refrigerant entering the compressor is compressed to high pressure and temperature in an isentropic manner.
Electrical motors play an important role in today’s society, from powering domestic appliances like blenders to industrial equipment such as trains. It almost seems impossible to not use an electric motor in our daily lives. In the comfort of our home, electric motors will operate fans, refrigerators, and air conditioners to just name a few. Researchers are constantly looking for new ways to incorporate electrical motors in our lives.