Experimental investigation of combustor effects on rocket thrust chamber performance

The results are reported of a program to develop special instrumentation systems and engine hardware, conduct tests using LOX/GH2 propellants wherein radial mixtures ratio stratification was controlled, and subsequently compare the results of four selected tests with the predictions of the JANNAF performance-prediction computer programs. During the experiments, the overall propellant mixture ratio was varied from 4.4 to 6.6, while the mixture ratios in the core and outer zone were varied from 5.7 to 8.8 and from 3.7 to 7.2, respectively. A nominal 10 percent of the total fuel flow was used as boundary layer collant in a majority of the firings. Nominal chamber pressure was either 225 or 250 psia, with nozzle expansion ratios of either 25:1 or 4:1. Measurements of the axial chamber pressure and wall heat flux profiles, together with samples of the exhaust gas, were obtained. The corrected experimental specific impulse and characteristic exhaust velocity efficiencies were approximately 97.5 and 98.5 percent, respectively

Noncircular Orifice Holes and Advanced Fabrication Techniques for Liquid Rocket Injectors (Phases 1, 2, 3, and 4)

A comprehensive summary of the results of a cold-flow and hot-fire experimental study of the mixing and atomization characteristics of injector elements incorporating noncircular orifices is presented. Both liquid/liquid and gas/liquid element types are discussed. Unlike doublet and triplet elements (circular orifices only) were investigated for the liquid/liquid case while concentric tube elements were investigated for the gas/liquid case. It is concluded that noncircular shape can be employed to significant advantage in injector design for liquid rocket engines

Correlation of spray dropsize distribution and injector variables Interim report

Correlation of spray drop size distribution and injector variable

High performance N2O4/amine elements: Data dump covering. Task 1: Literature review

The phenomenon of reactive stream separation (RSS) in the N2O4/amine earth-storable propellant combinations is reviewed. Early theoretical models of RSS are presented, as are experimental combustion data under simulated rocket conditions. N2O4/amine combustion chemistry data is also provided. More recent work in the development of a comprehensive model is described

Experimental verification of computer spray-combustion models

Analytical model formulation, representing performance of spray-combustion device, is based on understanding of atomization, mixing, vaporization, and combustion which occurs in device. Report lists results of correlations of computed values with values obtained from experiments with rocket combustor. Technique offers excellent method for evaluating validity and ranges of applicability of combustion models

Estimation of cavitation limits from local head loss coefficient

Cavitation effects in valves and other sudden transitions in water distribution systems are studied as their better understanding and quantification is needed for design and analysis purposes and for predicting and controlling their operation. Two dimensionless coefficients are used to characterize and verify local effects under cavitating flow conditions: the coefficient of local head losses and the minimum value of the cavitation number. In principle, both coefficients must be determined experimentally, but a semianalytical relationship between them is here proposed so that if one of them is known, its value can be used to estimate the corresponding value of the other one. This relationship is experimentally contrasted by measuring head losses and flow rates. It is also shown that cavitation number values, called cavitation limits, such as the critical cavitation limit, can be related in a simple but practical way with the mentioned minimum cavitation number and with a given pressure fluctuation level. Head losses under conditions of cavitation in sharp-edged orifices and valves are predicted for changes in upstream and downstream boundary conditions. An experimental determination of the coefficient of local head losses and the minimum value of the cavitation number is not dependent on the boundary conditions even if vapor cavity extends far enough to reach a downstream pressure tap. Also, the effects of cavitation and displacement of moving parts of valves on head losses can be split. A relatively simple formulation for local head losses including cavitation influence is presented. It can be incorporated to water distribution analysis models to improve their results when cavitation occurs. Likewise, it can also be used to elaborate information about validity limits of head losses in valves and other sudden transitions and to interpret the results of head loss tests

An investigation into the mechanisms that are steering large property owning organisations to implement green building features

Corporate social and environmental responsibility (CSR/CER) are terms that are often used to brand a company in a positive light. This does not necessarily mean that every organisation implements social and environmental initiatives with the same degree of vigour and commitment. South African property owning organisations are becoming increasingly aware that being socially and environmentally responsible can encompass the design and operation of their buildings. It is for this reason that these types of organisations are searching for ways to implement green building initiatives in their property portfolios. The implementation of environmentally friendly/green initiatives is viewed as Socially Responsible Property Investments (SRPI). Green building initiatives are slowly being adopted by some property owning organisations in South Africa, especially after the formal establishment of the Green Building Council of South Africa (GBCSA) in 2007. Implementation of green building initiatives have been met with multiple barriers by property owning organisations, such as lack of education by the professional team with regards to cost of green features and the processes involved in gaining green certification. Three prominent property owning organisations in Cape Town, two corporate and the other an academic institution were chosen as suitable case studies and analysed. Multiple respondents were interviewed for each case study and asked questions regarding their social and environmental initiatives and to what degree, if at all, they are attempting to implement green building features in their buildings. These questions were used to compare the organisation's actions to the content of its CSR policy. It was found that the adoption of green building initiatives was based on the type of property owning organisation, be it corporate or non-corporate. The property owning type has resulted in differing motives for implementation of green initiatives; however there are some common motives regardless of the company type, such as the financial feasibility of implementing said initiatives. The final results of this research revealed that although there is a small gap between a property owning company's CSR policy to that of its stated social and environmental initiatives, the gap between the CSR policy and its green building initiatives is still relatively large