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3. Fundamental Phenomena on Fuel Decomposition and Boundary-Layer Combustion Precesses with Applications to Hybrid Rocket Motors

Author

Kuo, Kenneth K, Lu, Yeu-Cherng, Chiaverini, Martin J, Johnson, David K, Serin, Nadir, Risha, Grant A, Merkle, Charles L, and Venkateswaran, Sankaran

Subjects
Spacecraft Propulsion And Power
Abstract

This final report summarizes the major findings on the subject of 'Fundamental Phenomena on Fuel Decomposition and Boundary-Layer Combustion Processes with Applications to Hybrid Rocket Motors', performed from 1 April 1994 to 30 June 1996. Both experimental results from Task 1 and theoretical/numerical results from Task 2 are reported here in two parts. Part 1 covers the experimental work performed and describes the test facility setup, data reduction techniques employed, and results of the test firings, including effects of operating conditions and fuel additives on solid fuel regression rate and thermal profiles of the condensed phase. Part 2 concerns the theoretical/numerical work. It covers physical modeling of the combustion processes including gas/surface coupling, and radiation effect on regression rate. The numerical solution of the flowfield structure and condensed phase regression behavior are presented. Experimental data from the test firings were used for numerical model validation.

Published
1996

4. Combustion of solid fuel slabs with gaseous oxygen in a hybrid motor analog

Author

Chiaverini, Martin J, Harting, George C, Lu, Yeu-Cherng, Kuo, Kenneth K, Serin, Nadir, and Johnson, David K

Subjects
Inorganic And Physical Chemistry
Abstract

Using a high-pressure, two-dimensional hybrid motor, an experimental investigation was conducted on fundamental processes involved in hybrid rocket combustion. HTPB (Hydroxyl-terminated Polybutadiene) fuel cross-linked with diisocyanate was burned with gaseous oxygen (GOX) under various operating conditions. Large-amplitude pressure oscillations were encountered in earlier test runs. After identifying the source of instability and decoupling the GOX feed-line system and combustion chamber, the pressure oscillations were drastically reduced from plus or minus 20% of the localized mean pressure to an acceptable range of plus or minus 1.5%. Embedded fine--wire thermocouples indicated that the surface temperature of the burning fuel was around 1000 K depending upon axial locations and operating conditions. Also, except near the leading edge region, the subsurface thermal wave profiles in the upstream locations are thicker than those in the downstream locations since the solid-fuel regression rate, in general, increases with distance along the fuel slab. The recovered solid fuel slabs in the laminar portion of the boundary layer exhibited smooth surfaces, indicating the existence of a liquid melt layer on the burning fuel surface in the upstream region. After the transition section, which displayed distinct transverse striations, the surface roughness pattern became quite random and very pronounced in the downstream turbulent boundary-layer region. Both real-time X-ray radiography and ultrasonic pulse echo techniques were used to determine the instantaneous web thicknesses and instantaneous solid-fuel regression rates over certain portions of the fuel slabs. Globally averaged and axially dependent but time-averaged regression rates were also obtained and presented. Several tests were conducted using, simultaneously, one translucent fuel slab and one fuel slab processed with carbon black powder. The addition of carbon black did not affect the measured regression rates or surface temperatures in comparison to the translucent fuel slabs.

Published
1995

5. Fuel decomposition and boundary-layer combustion processes of hybrid rocket motors

Author

Chiaverini, Martin J, Harting, George C, Lu, Yeu-Cherng, Kuo, Kenneth K, Serin, Nadir, and Johnson, David K

Subjects
Spacecraft Propulsion And Power
Abstract

Using a high-pressure, two-dimensional hybrid motor, an experimental investigation was conducted on fundamental processes involved in hybrid rocket combustion. HTPB (Hydroxyl-terminated Polybutadiene) fuel cross-linked with diisocyanate was burned with GOX under various operating conditions. Large-amplitude pressure oscillations were encountered in earlier test runs. After identifying the source of instability and decoupling the GOX feed-line system and combustion chamber, the pressure oscillations were drastically reduced from +/-20% of the localized mean pressure to an acceptable range of +/-1.5% Embedded fine-wire thermocouples indicated that the surface temperature of the burning fuel was around 1000 K depending upon axial locations and operating conditions. Also, except near the leading-edge region, the subsurface thermal wave profiles in the upstream locations are thicker than those in the downstream locations since the solid-fuel regression rate, in general, increases with distance along the fuel slab. The recovered solid fuel slabs in the laminar portion of the boundary layer exhibited smooth surfaces, indicating the existence of a liquid melt layer on the burning fuel surface in the upstream region. After the transition section, which displayed distinct transverse striations, the surface roughness pattern became quite random and very pronounced in the downstream turbulent boundary-layer region. Both real-time X-ray radiography and ultrasonic pulse-echo techniques were used to determine the instantaneous web thickness burned and instantaneous solid-fuel regression rates over certain portions of the fuel slabs. Globally averaged and axially dependent but time-averaged regression rates were also obtained and presented.

Published
1995

6. Fundamental phenomena on fuel decomposition and boundary-layer combustion processes with applications to hybrid rocket motors

Author

Kuo, Kenneth K, Lu, Yeu-Cherng, Chiaverini, Martin J, Harting, George C, Johnson, David K, and Serin, Nadir

Subjects
Spacecraft Propulsion And Power
Abstract

The experimental study on the fundamental processes involved in fuel decomposition and boundary-layer combustion in hybrid rocket motors is continuously being conducted at the High Pressure Combustion Laboratory of The Pennsylvania State University. This research will provide a useful engineering technology base in the development of hybrid rocket motors as well as a fundamental understanding of the complex processes involved in hybrid propulsion. A high-pressure, 2-D slab motor has been designed, manufactured, and utilized for conducting seven test firings using HTPB fuel processed at PSU. A total of 20 fuel slabs have been received from the Mcdonnell Douglas Aerospace Corporation. Ten of these fuel slabs contain an array of fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. Diagnostic instrumentation used in the test include high-frequency pressure transducers for measuring static and dynamic motor pressures and fine-wire thermocouples for measuring solid fuel surface and subsurface temperatures. The ultrasonic pulse-echo technique as well as a real-time x-ray radiography system have been used to obtain independent measurements of instantaneous solid fuel regression rates.

Published
1995

7. Measurement and simulation of regression rate development of a design code for hybrid rocket motors

Author

Serin, Nadir, Göğüş, A. Yalçın, and Diğer

Subjects
Havacılık Mühendisliği, Rocket fuel, Hybrid rocket motor, Aeronautical Engineering, Combustion instability, Simulation, Regression
Abstract

öz HİBRİD ROKET MOTORLARI İÇİN GERİLEME HIZI ÖLÇÜLMESİ VE BENZETİMİ VE BİR TASARIM KODUNUN GELİŞTİRİLMESİ SERİN, Nadir Doktora, Havacılık Mühendisliği Bölümü Tez Yöneticisi: Prof. Dr. A. Yalçın GÖĞÜS Mart 2001, 211 sayfa Hibrid roket motorlarının katı yakıt gerileme hızı deneysel olarak ve sayısal bir metodla araştırılmıştır. Ölçümler, gerçek zaman pals-eko ultrasonik tekniği ve gerçek zaman X-ray radyografi teknikleri ile gerçekleştirilmiştir. Detaylı bir veritabanı oluşturulmuş ve bir gerileme hızı modeli geliştirilmiştir. Ultrasonik ve X-ray radyografi ölçümlerinin basınç düzeltimi için yeni bir metod geliştirilmiştir. Ölçümler, Pennsylvania State Üniversitesi Yüksek Basınç Yanma Laboratuvarı'nda yapılmıştır. Test düzeneğinin yanma odası, gerileme hızım etkileyen önemli mekanizmaları anlamak için ticari bir Navier-Stokes bilgisiyar kodu olan CFD- ACE kullanılarak benzetilmiştir. İki problem çözülerek kodun geçerliliği sulanmıştır. Ardından hibrid roket motoru benzetimi türbülanslı aerodinamik, gaz haldeki kimyasal kinetik ve ısı geçişi etkilerini içeren CFD-ACE kullanılarak yapılmıştır. Yerel gerileme hızı, yüzey sıcaklığı ve yakıt besleme hızını CFD-ACE ile etkileşimli olarak hesaplamak amacıyla REGRESS programı yazılmıştır. Elde edilen gerileme hızlan, teorik ve deneysel sonuçlarla karşılaştırılmıştır. Toplam gerileme hızı ölçümlerine göre kabul edilebilir uyumluluk gözlemlenmiştir. Bugünkü hibrid yanma teorilerinin zayıflıkları bulunmuştur. Bu çalışmadaki önemli bir katkı, yeni bir hibrid roket motoru tasarım çözücüsü olan EULEC'in geliştirilmesidir. Bu çözücü, süreksiz, yaklaşık birboyutlu, denge yanma, Runge-Kutta yöntemi, açık, Euler çözücüsüdür. EULEC ile hesaplanmış toplam gerileme hızı ölçümlerle karşılaştırılmış ve iyi uyumluluk elde edilmiştir. EULEC ile akış özellikleri ve ürün kütle derişimleri için, CFD- ACE'inkilere yakın sonuçlar elde edilmiştir. Anahtar Kelimeler: Hibrdi Roket Motoru, HTPB Yakıtı, Gerileme Hızı, Yanma Kararsızlığı, Ultrasonik Ölçüm, X-Ray Radyografi, İnce Telli Isıl-çift, Navier- Stokes Çözücü, Düzlem Yakıcı, Konjuge Isı Geçişi,, Runge-Kutta. vı ABSTRACT MEASUREMENT AND SIMULATION OF REGRESSION RATE AND DEVELOPMENT OF A DESIGN CODE FOR HYBRID ROCKET MOTORS SERÎN, Nadir Ph.D., Department of Aeronautical Engineering Supervisor: Prof. Dr. A. Yalçın GÖ?ÜS March 200 1,211 pages Solid fuel regression rate of hybrid rocket motors was investigated both experimentally and numerically. The measurements were carried out by the real time pulse-echo ultrasonic technique and the real-time X-ray radiography technique. A detailed database was generated and a regression rate model was developed. A new method was developed for pressure correction of ultrasonic and X-ray radiography measurements. The measurements were performed at the High Pressure Combustion Laboratory of The Pennsylvania State University. The combustion chamber of the test set-up was simulated using the commercial Navier-Stokes computer code CFD-ACE, in order to understand the important mechanisms affecting the regression rate. The code was validated by solving two problems. The hybrid rocket motor analog was simulated using CFD- ACE taking into account turbulent aerodynamics, gaseous phase chemical kinetics and heat transfer effects. A program, REGRESS, was written in order to compute the local regression rate, surface temperature and fuel injection velocity interactively with CFD-ACE. The evaluated regression rates were compared with theoretical and experimental results and good agreement was observed in mcomparison to global regression rate measurements. The weaknesses of the present hybrid combustion theories were found. One important contribution of the present study is the development of a new computer code, EULEC, for hybrid rocket motor design. EULEC is a quasi one-dimensional, equilibrium combustion, Runge-Kutta scheme, explicit, Euler solver. The computed global regression rate of EULEC was compared with measurements and good agreement was obtained. The results attained with EULEC for flow properties and species mass concentrations are close to those of CFD- ACE. Keywords: Hybrid Rocket Motor, HTPB Fuel, Regression Rate, Combustion Instability, Ultrasonic Measurement, X-Ray Radiography, Fine- Wire Thermocouple, Navier-Stokes Solver, Flat-Flame Burner, Heat Transfer, Runge- Kutta. IV 211

Published
2001

9. An Experimental study on combustion instabilities

Author

Serin, Nadir, Göğüş, Yalçın, and Diğer

Subjects
Uçak Mühendisliği, Aircraft Engineering, Combustion instability
Abstract

öz YANMA KARARSIZLIKLARI ÜZERİNE DENEYSEL BİR ÇALIŞMA SERİN, Nadir Yüksek Lisans Tezi, Havacılık Mühendisliği Anabilim Dalı Tez Yöneticisi : Prof.Dr. A. Yalçın GÖ?ÜS Yardımcı Tez Yöneticisi : Prof.Dr. Demir BAYKA Eylül, 1993, 76 sayfa Yanma kararsızlıkları havacılık itki sistemlerinin ve endüstriyel yanma odalarının önemli sorunlarıdır ve büyük arızalara neden olabilirler. Bu çalışmada, genişliyen borudaki alçak frekanslı yanma kararsızlıklarını inceliyerek yanma kararsızlıklarının kaynağı konusunda daha fazla bilgi edinmek amaçlanmıştır. Deneylerde kullanılan ölçme metodlannın doğruluğu sınandı, akışın ve geometrideki değişimlerin sistem akustiğine olan etkileri belirlendi. Düşük frekanslı yanma odası kararsızlığında frekans tercihleri belirlendi. Yanma kararsızlığı deneyleri sonucunda, alevin görüldüğü bölgedeki akustik hız titreşimlerinin alev alanında, böylece ısı ilavesinde titreşimlere sebep olduğu gözlendi. Yerel şartların kararsızlık getirip getirmeyeceği basınç maksimumu ile hız maksimumu üzerinden, ısı ilavesi maksimumu arasındaki zaman aralığının büyüklüğüne bağlıdır. Anahtar Kelimeler : Yanma kararsızlığı, Rayleigh kriteri, borularda akustik. Bilim Dalı Sayısal Kodu : 618.01.03 iv ABSTRACT AN EXPERIMENTAL STUDY ON COMBUSTION INSTABILITIES SERÎN, Nadir M.S. in Aeronautical Engineering Supervisor : Prof.Dr. A. Yalçın GÖ?ÜS Co-Supervisor : Prof.Dr. Demir BAYKA September, 1993, 76 pages Combustion instabilities pose crucial problems in aerospace propulsion units as well as in industrial combustion chambers and may cause catastrophic failures. To have a better knowledge about the origin of chamber instabilities and frequency selection by investigating low frequency chamber instability in a divergent duct is the main purpose. The measurement techniques used are verified, the influences of flow field and variable cross- section on system acoustics are experimentaly determined. The frequency selection of the low frequency chamber instability in a divergent duct is evaluated. It has been observed that acoustic velocity fluctuations result in fluctuations of flame area, hence of heat release. Local conditions may or may not cause instability depending on the time lag between the pressure maximum and heat release maximum, via velocity maximum. Key Words : Combustion instability, Rayleigh criterion of combustion instability, acoustics in ducts. Science Code: 618.01.03 m 74

Published
1993

16. Analysis of internal explosion and structural response to blast loading

Author

Turcan, Uğur Can, Ulaş, Abdullah, Serin, Nadir, and Makine Mühendisliği Anabilim Dalı

Subjects
Air blast, Mechanical Engineering, Explosion, Structural change, Makine Mühendisliği, Experiments, Scaling
Abstract

Kapalı hacimlerde meydana gelen patlamalar sonucu oluşan darbe basıncı yükleri ve bu yüklerin yapılarda oluşturduğu dinamik davranışlar çözümlenmiştir. Tedarik edilebilen ticari yazılımlar hem darbe basıncını hem de yapısal davranışı çözebilmektedir. Fakat üç boyutlu çözümlemeler yüksek miktarda işlemci zamanı gerektirmektedir. Diğer taraftan, literatürde yer alan ampirik yaklaşımlar kısıtlı miktarda probleme uygulanabilmektedir. Bu çalışmanın amacı iki yöntemi birleştirerek kısa zamanda kabul edilebilir sonuçlar elde edebilmektir. Blast loads due to internal explosion and dynamic response to this loading of the structure will be analyzed. Commercial codes require a lot of cpu time to solve both the blast and the response in three dimensions. On the other hand, empirical approaches are not applicable to various problems. The aim of this work is to get satisfactory results in relatively short time by combining these two methods. 148

Published
2012

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