Effectiveness of wheel-typed grain design for hybrid rocket motor performance

Although hybrid rockets are featured with distinct advantages over solid and liquid rockets, the issues specifically related to combustion instability and lowered regression rate are the most pronounced drawbacks which hinder it from being commercially viable. In the present work, we investigate the characteristics of hybrid rocket performance using generic algorithm code for preliminary design analysis purposes. An interior ballistic model is used for the analysis of the hybrid rocket performance. MATLAB® environment is used to develop the design and performance analysis codes, and visualize the temporal variation of performance characteristics. Hydroxyl Terminated Polybutadiene (HTPB) is used as a solid fuel and liquefied oxygen as an oxidizer for evaluation purposes. We have evaluated some other design features such as different expansion ratio for nozzle, different oxidizer initial flux and variation of initial mass. The valuation of variety port numbers are presented as well as comparison of multiple circular grain design. It was found that wheel-typed grain design improves 5% on the regression rate. The uses of many ports also improvise the regression rate but require a large diameter for structural integrity

Enhancement of polymerase chain reaction using graphene nano-flakes

The excellent heat transfer properties of nanoparticles have potential applications in various fields including biology during the last two decades. Recently, the use of various nanoparticles in polymerase chain reaction (PCR) resulted in significant enhancement of its efficiency and specificity. In this research we have demonstrated the effects of a novel material, graphene nano-flakes on PCR. The rationale behind the use of graphene flakes is its unique physical and heat transfer properties. A number of experimental results including the effect of graphene flakes on denaturation of DNA and annealing step will also be discussed. The preliminary results clearly show that enhanced heat transfer effect of nano-flakes augment PCR yield and ultimately overall enhancement in reaction efficiency

Investigation of heat transfer effect on polymerase chain reaction

This report presents the final results of the research project titled “Investigation of heat transfer effect of nanoparticles on PCR”. In this research we have demonstrated the effects of a novel material, graphene nano-flakes on PCR. The rationale behind the use of graphene flakes is its unique physical and heat transfer properties. A number of experimental results including the effect of graphene flakes on denaturation of DNA and annealing have been discussed. The preliminary results clearly show that enhanced heat transfer effect of nano-flakes augment PCR yield and ultimately overall enhancement in reaction efficiency

Modelling ion propulsion plume interactions with spacecraft in formation flight

This paper presents a simulation study of ion thruster plume effects on formation flying spacecraft. Two formation flight applications using micro-ion propulsion are considered: an L2-Halo orbit interferometer formation and a LEO micro-satellite formation. Worst case scenarios in both missions have been investigated. We focus our study on thruster configurations resulting in possible indirect plume impingement on satellites outside of the direct impingement zone. Indirect impingement which cannot be predicted except through plasma simulation or in-flight measurements might expose critical spacecraft elements such as optical sensors to a harsh contamination environment. A high-fidelity electrostatic plasma simulation code for parallel computing platforms was used in the study. In our study, we found that using miniature scale ion propulsion in both formation missions creates a very low charge-exchange plasma environment which results in tolerable contamination environment for other spacecraft in the formation

Assessment of free-rotating air swirling device to reduce SI engine emissions and improve fuel economy

Claims are furnished in several patents that swirling the intake air in SI engines can improve fuel economy and reduce environmental impact. In this paper, we investigate the effect of a free rotating air swirling device (FRASD) installed in the air intake hose on the overall performance and emission characteristics of an SI engine. FRASDs with three vane angles were tested; 6, 9 and 12 degrees. The baseline engine was tested without FRASD at selected loads. Then, the engine was tested at the same loads with each FRASD and results were compared with the baseline engine. Experiments show that all tested FRASDs exhibit some degree of enhancement in the overall performance and reduction in exhaust emissions. It was found that enhancement greatly depends on the engine operating condition in addition to the FRASD vane angle. Specifically, best enhancement in performance and highest reduction in emissions was observed with the 9-degrees which reduced specific fuel consumption by 12%, hydrocarbon (HC) emissions by 20% and carbon monoxide emissions by 12%. Suggestions are made to modify the FRASD design to magnify its impact on engine performance

Effect of varying design options on the transient behavior of a hybrid rocket motor

Hybrid rockets provide compelling features for use in atmospheric and space rocket propulsion. One of the prominent applications of hybrid rockets which foster on its characteristics is the propulsion of micro air launch vehicles. In this paper, a set of design options of a hybrid rocket motor is evaluated for propulsion of micro air launch vehicles. In order to evaluate the various design options of a hybrid rocket, we developed design and performance simulation codes. A simulation code is based on a legacy interior ballistic model. MATLAB® environment was used to develop the design and performance analysis codes and to visualize the temporal variation of performance characteristics and grain geometry during burning. We employ the developed codes to assess the replacement of solid rocket motors which are typically used in Air Launch Vehicles by hybrid rocket motors. A typical Micro Air Launch Vehicle mission to launch a 20-kg payload into a 400-km circular polar orbit is assumed. The results show that a hybrid rocket is a suitable candidate for micro air launch vehicles. The performance is improved in terms of specific impulse and thrust with smaller size in the same mission. Several design parameters of hybrid rocket motors were also evaluated and analyzed, including different fuel port geometry, type of fuels and oxidizers, number of ports, nozzle design and initial mass flux. These design parameters bring a significant effect on hybrid rocket performance and size

Vehicle fuel consumption and emission modelling: an in-depth literature review

Modelling of vehicle fuel consumption and emissions has emerged as an effective tool to help develop and assess vehicle technologies and to help predict vehicle fuel consumption and emissions. A review to identify the current state-of-the-art on vehicle fuel consumption and emissions modelling is elucidated. This review categorises vehicle fuel consumption and emissions models into five classifications. The relevant main models to each of these classifications are presented. These models are then compared with regard to assumptions, limitations, merits, drawbacks, characteristic parameters, data collection techniques, accuracy, and relevance to road traffic. The study demonstrates that the trends of vehicle fuel consumption and emissions provided by current models generally do satisfactorily replicate field data trends. In addition, the paper demonstrates that mesoscopic models, empirical models, mean value-based models, and quasi dimensional models strike a balance between accuracy and simplicity and thus are very suitable for transportation and control applications. The study shows as well that no one model as yet fully meets the needs of transportation applications

Orifice plate flowmeter performance under pulsating flow conditions

Current need for cost and energy savings increases the demand for accurate measurement of mass flow rate. Measuring flow rate through a pipe is an important process in many industries, such as natural gas transport, feeding systems in petrochemicals, automotive and hydraulic applications. Pressure differential devices such as orifice plate are used extensively because of their simplicity and low cost maintenance. When flow pulsations exist, flow measurement errors are unavoidable. In this research, the performance of an orifice plate flow meter is assessed numerically using STAR-CCM+ software. Incompressible 2-D turbulent flow is considered for Re=1.5×104 to Re=5×105. Numerical simulations of steady flow are conducted to evaluate the discharge coefficient of the orifice. The grid is chosen based on grid independency study. The discharge coefficient is compared favorably with ISO value. For unsteady flow, time independency study is conducted to determine the time step. Unsteady flow rate measurement error due to pulsation is calculated for different frequencies. The results showed good agreement between calculated mass flow rate and simulated measured mass flow rate