ISSUE OF SHOCK COMPRESSION AND EXPANSION BY DISPLACEMENT COMPRESSORS VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 ISSUE OF SHOCK COMPRESSION AND EXPANSION BY DISPLACEMENT COMPRESSORS Ing. Zdeněk Šmída doc. Ing. Kamil Kolarčík, CSc.

Content of presentation VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 Content of presentation Reasons for opening this issue Brief description of the accident Subjects of research Phenomena of research Shock compression Shock expansion Measurement Description of meter run Description of 1. measurement Description of 2. measurement Conclusions ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

Reasons for opening this issue VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 Reasons for opening this issue Shock compression and expansion are theoretically know phenomena without deeper understanding Efforts to open a discussion on academic and industrial ground Accident of mobile compressor units with screw compressor Compressor unit was located in the one company in the MS region The extent of damage raised a range of questions about the real influence of these phenomena ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

Scheme of the compressor unit XAH 4 PTO VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 Scheme of the compressor unit XAH 4 PTO AF – air filter (inlet side) E – compressor AR – oil separator OS – steel basket with oil filter AV – ball valve (outlet side) RV – control valve Co – oil cooler FN – fan OF – oil filter ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 Causation of accident Failure change of air filters Pollution and impassibility of oil filter in oil separator Increase of pressure difference between inlet and outlet side of oil separator These events were making for collapse of steel basket of oil separator ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

After-effects of destruction of oil separator VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 After-effects of destruction of oil separator Without oil separator it begun attend to lossing of oil from compressor to pipe system Without oil in compressor it begun increase the friction losses and temperature in working space of compressor That two effect was proving in ignition of oil vapour and in fire which was destroying compressor unit ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 Subjects of research Shock compression and expansion are not occurring by all types of displacement compressors Problems have only these compressors which have build-in pressure ratio π [-] (defined by manufacturer) This compressor can compress gas only to design pressure regardless to pressure in the pipe system. Build-in pressure ratio π [-] can be different by total pressure ratio of pipe system σ [-] Screw compressors Vane compressors ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

Shock compression and expansion VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 Shock compression and expansion Definition 1: Shock compression and expansion are the negative phenomena which occur when is build-in pressure ratio π [-] in imbalance with total pressure ration of pipe system σ [-] Definition 2: These phenomena occur when is pressure on the outlet of compressor p2 [Pa] different from pressure in the pipe system pD [Pa]. These phenomena are proving pressure pulsation, energy losses and instability working process of compressor ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 Shock compression The condition: π < σ (p2 < pD) 1. Polytrophical compression 2. Shock compression Short backflow of compress gas (recirculating losses) Gas which has higher enthalpy are increasing temperature of still compressing gas. Result of this is the increase of compressing work by aztr [J]. Pressure pulsations Higher axial forces on bearings Increase temperature of gas Increase of power consumption Increase of operation costs. ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 Shock expansion The condition: π > σ (p2 > pD) 1. Expansion to „empty“ pipe system Pressure pulsation can damage devices on the outlet side of compressor. 2. Compressing of gas to useless high pressure Need more compressing work by aztr [J]. Need more compressing work Need more power consumption Worse economy of operation ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

Measurement of shock compression and expansion VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 Measurement of shock compression and expansion Laboratory of the displacement compressors Meter run is design by MATTECH, s.r.o. company Actual source of compress air: Mobile compressor unit SE 25 with screw compressor NK 40 (Atmos – Chrást, s.r.o.) ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 The core of meter run For simulation of real shock compression and expansion are using pressure cylinders. 5 pressure cylinders (V=29 l) are unexchangeable 1 pressure cylinder can be changing. We have two posibility volume: 1 l or 0,5 l All pressure cylinders have sensing devices of temperature and pressure. Two pressure cylinders have more sensing devices for higher accuracy of measurement. We can change total pressure ratio of the pipe system σ [-]. ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

Measurement without influence to compressor VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 Measurement without influence to compressor This measurement analyzes the influence of shock compression and expansion to devices on the outlet side of compressor. We have more combination which we can use for achievement of total pressure ratio of the pipe system σ [-]. Self process of simulation is the „overflow“ from cylinders by higher pressure to cylinders by lower pressure. If we use the overflow we get: Pressure pulsations Energy losses Shock compression and expansion ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

Measurement with influence to compressor VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 Measurement with influence to compressor This measurement analyzes the influence of shock compression and expansion to self compressor. Self process of simulation is the „overflow“ from cylinders by higher pressure to „empty“ pipeline and to compressor. If we use the overflow we get again: Pressure pulsations Energy losses Shock compression and expansion ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

What we waiting for about these measurements VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 What we waiting for about these measurements Phase I Check theory in the practical measurement Quantification of these theoretically information Assumption of changes power consumption Numerical data for specification phase II Phase II According results from Phase I ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 Why we do that… Phase Check of influence these phenomena to real devices Measurement on more compressors for comparing of results Evaluation of 1. phase Finding solution of degreasing influence these phenomena to real compressors Effects: Increasing safety of operation Increasing of efficiency Better economy of operation Degreasing of operation and service costs ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK

Thank you for your attention VŠB - TECHNICAL UNIVERSITY OF OSTRAVA FACULTY OF MECHANICAL ENGINEERING DEPARTMENT OF POWER ENGINEERING OSTRAVA, CZECH REPUBLIC WWW. FS.VSB.CZ/361 Thank you for your attention QR VCARD QR FACEBOOK www.fs.vsb.cz/361, www.fb.com/katedra.energetiky ISSUE OF SHOCK COMPRESSION AND EXPANSION Z. ŠMÍDA, K. KOLARČÍK