[Mechanical Equipment Technology Edition] Daily Question 20171104: Thermal Performance of Screw Compressors (2)
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This post was last edited by YORK Industrial Refrigeration on 2017-11-11 at 09:16. Starting from now, in order to enhance communication among users, a \"Question of the Day\" activity has been launched on the Mechanical Equipment Technology forum. We hope everyone will participate actively to progress and improve together! ! ! Rewards: 3 wealth points for active participation, 10-15 wealth points for correct answers. This question is valid for two days; no scoring will be given after that period. Last time we discussed what the gas delivery coefficient is, and this time we will ask what factors affect the gas delivery coefficient of screw compressors. Answer: ① Leakage: Gas leaks through gaps, which can be either external leakage or internal leakage. Leakage refers to the escape of high-pressure gas into the intake duct or the tooth cavity that is currently drawing in air ； Leakage is the leakage between the elementary volume isolated from the intake pipe. External leakage is what affects volumetric efficiency, while internal leakage only increases power consumption. ② Inlet loss: The dynamic loss that occurs as gas passes through the inlet pipes and orifices, which reduces the inlet pressure, decreases the density of the gas being drawn in, and accordingly reduces the amount of gas drawn in by the compressor. ③ Heating loss: The rotor and the casing are heated by the compressed, high-temperature gas, resulting in temperatures that are much higher than those of the incoming gas. During the intake process, the low-temperature gas expands due to heating from the intake pipe, rotor, engine body, and the injected oil, thereby reducing the amount of gas drawn in by the compressor. ④ The enclosed volume and the centrifugal force exerted on the gas as the rotor rotates also affect the amount of gas drawn in. Among the factors that affect volumetric efficiency, the most important one is leakage. The magnitude of the leakage is related to factors such as operating conditions, oil injection status, circumferential speed, tooth shape, gap size, and manufacturing precision. ================================ High-quality promotions: Mechanical equipment---Maintenance procedures for York screw compressors https://bbs.hcbbs.com/thread-1806833-1-1.html Mechanical equipment---Upgrading of York Quinton control centers https://bbs.hcbbs.com/thread-1804837-1-1.html Mechanical equipment---Major repairs for GEA Grasox screw compressors https://bbs.hcbbs.com/thread-1800467-1-1.html Mechanical equipment---Disassembly and maintenance of British HOWDEN screw compressors https://bbs.hcbbs.com/thread-1832529-1-1.html Mechanical equipment---Disassembly and maintenance of Japanese Maekawa MYCOM screw compressors https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1786445
① Leakage: Gas escapes through gaps, and it can be divided into external leakage and internal leakage. Leakage refers to the escape of high-pressure gas into the intake duct or the tooth cavity that is currently drawing in air ； Leakage is the leakage between the elementary volume isolated from the intake pipe. External leakage is what affects volumetric efficiency, while internal leakage only increases power consumption. ② Inlet loss: The dynamic loss that occurs as gas passes through the inlet pipes and orifices, which reduces the inlet pressure, decreases the density of the gas being drawn in, and accordingly reduces the amount of gas drawn in by the compressor. ③ Heating loss: The rotor and the casing are heated by the compressed, high-temperature gas, resulting in temperatures that are much higher than those of the incoming gas. During the intake process, the low-temperature gas expands due to heating from the intake pipe, rotor, engine body, and the injected oil, thereby reducing the amount of gas drawn in by the compressor. ④ The enclosed volume and the centrifugal force exerted on the gas as the rotor rotates also affect the amount of gas drawn in. Among the factors that affect volumetric efficiency, the most important one is leakage. The magnitude of the leakage is related to factors such as operating conditions, oil injection status, circumferential speed, tooth shape, gap size, and manufacturing precision.
1. Leakage The leakage of gas from screw air compressors through gaps can be divided into external leakage and internal leakage. External leakage affects the gas delivery coefficient, while internal leakage only impacts the power consumption of the screw air compressor. 2. Suction pressure loss When gas passes through the compressor’s suction ducts and suction inlets, flow losses occur, resulting in a decrease in suction pressure and an increase in specific volume. This, in turn, reduces the amount of gas drawn in by the compressor and lowers its volumetric efficiency. 3. Preheating loss: During the suction process, the gas expands due to heating by the suction ducts, rotor, and casing, which accordingly reduces the amount of gas drawn in and lowers the compressor’s volumetric efficiency.
①Effect of clearance volume； ②Effect of suction and exhaust resistance ； ③Effects of inhaling superheated steam ； ④Impact of leaks.
1. Leakage The leakage of gas from screw air compressors through gaps can be divided into external leakage and internal leakage. External leakage affects the gas delivery coefficient, while internal leakage only impacts the power consumption of the screw air compressor. 2. Suction pressure loss When gas passes through the compressor’s suction ducts and suction inlets, flow losses occur, resulting in a decrease in suction pressure and an increase in specific volume. This, in turn, reduces the amount of gas drawn in by the compressor and lowers its volumetric efficiency. 3. Preheating loss: During the suction process, the gas expands due to heating by the suction ducts, rotor, and casing, which accordingly reduces the amount of gas drawn in and lowers the compressor’s volumetric efficiency.
#Here briefly, 1. The impact of clearance volume； II. Influence of adsorption and exclusion resistance ； III. Effects of inhaling superheated steam ； IV. Response on the Impact of Leaks#
The main ones are: first, the influence of clearance volume； II. Influence of adsorption and exclusion resistance ； III. Effects of inhaling superheated steam ； IV. Impacts of leaks
1. Leakage The leakage of gas from screw air compressors through gaps can be divided into external leakage and internal leakage. External leakage affects the gas delivery coefficient, while internal leakage only impacts the power consumption of the screw air compressor. 2. Suction pressure loss When gas passes through the compressor’s suction ducts and suction inlets, flow losses occur, resulting in a decrease in suction pressure and an increase in specific volume. This, in turn, reduces the amount of gas drawn in by the compressor and lowers its volumetric efficiency. 3. Preheating loss: During the suction process, the gas expands due to heating by the suction ducts, rotor, and casing, which accordingly reduces the amount of gas drawn in and lowers the compressor’s volumetric efficiency.
1. Leakage The leakage of gas from screw air compressors through gaps can be divided into external leakage and internal leakage. External leakage affects the gas delivery coefficient, while internal leakage only impacts the power consumption of the screw air compressor. 2. Suction pressure loss When gas passes through the compressor’s suction ducts and suction inlets, flow losses occur, resulting in a decrease in suction pressure and an increase in specific volume. This, in turn, reduces the amount of gas drawn in by the compressor and lowers its volumetric efficiency. 3. Preheating loss: During the suction process, the gas expands due to heating by the suction ducts, rotor, and casing, which accordingly reduces the amount of gas drawn in and lowers the compressor’s volumetric efficiency.
The main factors affecting the gas delivery coefficient of a compressor are: 1. The influence of clearance volume； II. Influence of adsorption and exclusion resistance ； III. Effects of inhaling superheated steam ； IV. Impacts of leaks.
The main ones are: first, the influence of clearance volume； II. Influence of adsorption and exclusion resistance ； III. Effects of inhaling superheated steam ； IV. Impacts of leaks