One, centrifugal type is constrictive the secondary of machine is tectonic
1, impeller (blade annulus)
Be bring to bear on to air of kinetic energy local, coming over is with what cast subtly means is consumed, but leaving call in 5 axes machine high speed after machine, more uses the means that cutting machines. Number is little when the practice of this kind of means consumes labour, capital is costly. Its material is qualitative common used the titanium alloy that won't corrode or stainless steel.
Look from the principle, constrictive progression is close to more more more at isotherm constrictive, its efficiency is taller. If ponder the pressure loss of bicephalous condenser and axis to seal what installation happens to divulge, 2 class are constrictive the difference of as constrictive as 3 class efficiency is about 3.5% , 3 class are constrictive the difference of as constrictive as 4 class efficiency is about 1% .
Rise as a result of what fluid numerical value analyses, its deal with software once nonexistent purchase a doorsill, consequently old brand manufacturer builds up in technology and data the advantage of the respect once die. The efficiency of impeller monomer also arrives 95% , already did not improve margin how oldly.
Because do screw to the contact of the screw of constrictive machine and screw can scorch and be damaged, the management to precision is very consequently fundamental, but centrifugal type is constrictive the impeller even if of machine and spiral case fit are nominal the contact also will not scorch and fit accident. The impeller in movement because the deformation of the deformation of centripetal force occasion or spiral case, the exit that causes the vane wheel when practice runs is not put in aperture. If fractionation examination stops after movement ends, state of large minority leaves the mark that can acknowledge subtle contact. That is to say its construction is very restful.
Stop to quicken to the air of impeller decelerate, transform the installation that is pressure is called diffuser.
If do not take blade (without blade type) criterion air much edge is circumferential directional activity, reach downstream eddy room (spiral case) interval lengthens. Common, alter air current angle through device stationary lamina the interval that direction of the radius that it is an edge will come to to lengthen a course, increase the attrition loss of access. Type of channel of this access existence, blade type, wait without blade type.
The Xiaozhan great that the professor of benefit of peaceful of younger sister end of university of a poetic name of China released his to develop in ASME 1983 compares blade diffuser (low density) , very applicable inside efficiency and discharge limits, lose use generally of the whole world. Professor of benefit of peaceful of younger sister end was not requesting patent beforehand, consequently this technology is applied inside alive bound limits unlimited.
Shed brawn to learn in the center, want to compare decelerate difficulty quickly to airy. Consequently the improvement of diffuser develops difficulty to want prep above to rotate the development of impeller, apply the caustic keep a promise that go up to be in in practice at present 10% the left and right sides, still put in the space that increase, remain further development is improved.
2, centrifugal type is constrictive the characteristic of machine
1, breathe heavily brace up
Constrictive machines and tools has centrifugal type the asthma that cubage type place does not have brace up characteristic.
When discharge adds a certain boundary line, diffuser and impeller can present stall (Stall) , downstream air is germinant and refluent swim downward. Below this discharge borderline, fit of exhaust side air is measured completely refluent, be being contracted quickly downstream by constrictive air downstream, can produce explosive sound. Should make the pressure of exhaust side drops quickly upstream, rise again after and break out again refluent, picture of this kind of oscillation is called the asthma of turbine brace up.
As a result of occasion the stall that the cause of this picture is diffuser or impeller, want to ponder the measure that avoids this stall consequently. The kinetic energy that brings to bear on in impeller is issued for the state of pressure by often change, the cause of stall is too big acceleration. Once fit reduces an amount, this kind of common accelerator meets diffuser most first germinant stall, some designs also have can present impeller first the state of stall.
Impeller is machine of decelerate of a kind of air, common do not think its can present stall, but if if come from impeller and airy absolute velocity,pondering, also can appear in impeller quickly. If want to be able to prevent stall, can reduce diffuser or impeller increase speed ratio, but the length that can add radius direction to go up so, the attrition loss inside access can be added as the accretion of this length into scale. How to reduce the carapace that take energy of life (spiral case) will be quickened invalidly, it is the key of technology of ascensive centrifugal function. Also be likened to what do not take blade without interval of access of blade type diffuser long, the loss can be added, but on the other hand its take blade form than wanting to compare quickly small, break out not easily consequently stall.
Below adverse condition, when running namely, do not alter revolution reduces flow, ascensive pressure is compared, the exhaust temperature of constrictive machine meets dry screw rise, screw can scorch injury, consequently its contain exhaust temperature to rise to spark namely stop the restful installation of machine. Constrictive machine also contains centrifugal type prevent to breathe heavily brace up control installation, but become effective of even if control presented asthma brace up, common also won't occasion injury, it can cross temperature of big or refluent air to inlet temperature rises and stop namely as a result of vibration machine.
2, discharge recuperates limits
Centrifugal type is constrictive the characteristic of machine is, take gas a powerful person through decreasing, can increase into tolerance not merely, OK still shift effect point, reduce inlet pressure to press compared heighten in order to increase. And the key that masters recuperation range, depend on how preventing aforementioned to breathe heavily brace up.
Want to go after highest efficiency, the acceleration that can increase impeller and diffuser ability, reduce access loss, but because the addition of discharge is very fast,can present stall. On criterion, pursueing highest efficiency and range of recuperation of the largest flow at the same time is contradictory. The product in the market is freewill made fair compromise.
The technology of scope of patulous discharge recuperation in refrigeration agent or supercharger of car engine turbine is very mature already, technology of the diffuser bypass technique that shuns diffuser stall, diffuser reduce expenditure and the technique that shun impeller to export local stall already had relevant product.
These technologies can expand the discharge of constrictive machine recuperates centrifugal type limits, make constrictive machine regards centrifugal type as equipment of recuperation of a kind of capacity constrictive machine stops invalid ground and screw of frequency conversion type contrary.
3, centrifugal type is constrictive the actor blemish of machine
① did not wear away, safeguard capital to be in constrictive machine lowest;
Constrictive machine photograph compares ② and screw style, of aperture happening divulge little, the efficiency of only course is consequently tall;
Constrictive machine photograph compares ③ and dry type screw, spare parts amount and treatment industry duration are little, treatment precision demand is not high, consumptive capital is low.
In heat systole or stress issue meeting fit deformation when constrictive machine break down and movement, aperture can break out change.
Dry screw is constrictive two screw of machine with the face absolutely, consequently its characteristic is contact of in a way can make surface contact, occasion is calorific and contractive, scorch and get stuck dead, and on the other hand, centrifugal type is constrictive the characteristic with the greatest opportunity, it is impeller blades and spiral case be with the line absolutely, consequently even if breaks out a certain number of contacts also are line contact, if blade has delimited like bit, won't scorch. Consequently, its biggest advantage is an accident more constrictive than working type screw confidential is gotten less much.
① air access is local (impeller and diffuser) purify outsidely can bring about the function is reduced
The function can be reduced about 10% the left and right sides. But expend power to also can increase. Because airy speed is every second hundreds meters, consequently the coarse level of interface appearance has great effect to the function, especially the diffuser with the rapiddest velocity of flow purifies an influence locally the biggest. Of course, except purify besides, corrode unusual meeting makes appearance coarse and reduce a function.
Want to handle this success, can progress of the inhaler filter precision, and current applies exterior (impeller and diffuser) clean. In addition, centrifugal type is constrictive the function of machine inhaler is common want prep above other type, and have very large area for the life of outspread filter core, some users are applied than gas turbine (gas turbine also is machinery of a kind of turbine, have contrary drawback consequently) the filter with taller function will avoid a function to reduce, its filter core can be twined automatically also facilitate safeguard. Early of shipping turbine supercharger was thrown with respect to the method that cleans current gush water impeller and diffuser applicable, but this method was not used in ocean turbine machinery it seems that, the user also does not pay close attention to this.
Investment of ② initial stage is high
Screw type and piston are constrictive the commercial form of aircraft manufacturer is to rely on safeguard cost to receive profit back and forth, can give out consequently inferior price. But constrictive machine does not have centrifugal type too much maintenance project, capital of even if consumption is consequently costly, also must raise high-spirited price.