Derating design for optimizing reliability and cost with an application to liquid rocket engines

Kim, Kyungmee O.; Roh, Tae‐Seong; Lee, Jae Woo; Zuo, Ming J.

doi:10.1016/j.ress.2015.10.005

Cited by 12 publications

(15 citation statements)

References 13 publications

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“…The working medium for the experiments is liquid nitrogen. The density and viscosity of liquid nitrogen are 813.7 kg/m 3 and 82.3×10 −6 Pa•s, respectively. During the experiments, high-pressure liquid nitrogen is pumped into the cavities through orifice throttles with a diameter of 0.5 mm.…”

Section: Fluid-film Bearingsmentioning

confidence: 99%

“…The current compromise approach is the widespread use of mature rocket products, which undoubtedly restricts further improvement of aerospace technologies. There is already a worldwide agreement that the reusable rocket is the most promising approach to cut down the launch cost [3,4]. It is well known that the NASA space shuttle was the first-generation of reusable launch vehicles in human history.…”

Section: Introductionmentioning

confidence: 99%

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An Overview of Bearing Candidates for the Next Generation of Reusable Liquid Rocket Turbopumps

Miao

et al. 2020

Chin. J. Mech. Eng.

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There is a consensus in the aerospace field that the development of reusable liquid rockets can effectively reduce the launch expense. The pursuit of a long service life and reutilization highly depends on the bearing components. However, the rolling element bearings (REBs) used in the existing rocket turbopumps present obvious and increasing limitations due to their mechanical contacting mode. For REBs, high rotational speed and long service life are two performance indexes that mutually restrict each other. To go beyond the DN value (the product of the bearing bore and rotational speed) limit of REBs, the major space powers have conducted substantial explorations on the use of new types of bearings to replace the REB. This review discusses, first, the crucial role of bearings in rocket turbopumps and the related structural improvements of REBs. Then, with the prospect of application to the next generation of reusable liquid rocket turbopumps, the bearing candidates investigated by major space powers are summarized comprehensively. These promising alternatives to REBs include fluid-film, foil, and magnetic bearings, together with the novel superconducting compound bearings recently proposed by our team. Our more than ten years of relevant research on fluid-film and magnetic bearings are also introduced. This review is meaningful for the development of long-life and highly reliable bearings to be used in future reusable rocket turbopumps.

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Section: Fluid-film Bearingsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Overview of Bearing Candidates for the Next Generation of Reusable Liquid Rocket Turbopumps

Miao

et al. 2020

Chin. J. Mech. Eng.

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“…1 with blue line). Where, and are depending on [7,8,34, 45] and resulted from the lookup function. Next, considered as , and and are regarded as .…”

Section: Cost Of Reliability and Unreliabilitymentioning

confidence: 99%

“…as the optimal value of based on the minimum that computed by using Eq. (8). Next, is the fixed value of service time that used to compute the reliability and its costs.…”

Section: Finally In Codsr Model Presented We Getmentioning

confidence: 99%

“…System reliability might have two types of cost, namely reliability cost (such as the cost to improve maintenance, the cost to improve quality, the inventory cost of component [1][2][3]) and unreliability cost (such as the cost of reliability decrease, damage cost, loss sales [4][5][6]). Commonly, both costs could be non-linear and opposite each other [7,8]. This condition causes the opportunity cost when the reliability of a system is high, it causes reliability cost increase, and unreliability cost decrease and another hand, if it is low, reliability costs decrease and unreliability cost increase.…”

Section: Introductionmentioning

confidence: 99%

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Cost Optimization of Dynamic Service Reliability: A Case Study of Demand Fulfillment on Enterprise

Mudjahidin¹,

Buliali²,

Yuniarto³

2019

IJIES

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As a system, private industrial network (PIN) could be computed its service reliability for a specific duration time where the service reliability has two cost components (reliability costs and unreliability cost) which opposite and non-linear. Furthermore, in the PIN, service reliability could have the effect to demand, and the demand also influenced by the external factor. For this reason, we propose a computation of service reliability and find the optimized service time, which can minimize the total reliability cost and unreliability cost for a specific duration time. Furthermore, in this proposed model, reliability and external have the effect to demand. Based on the case study, we implement and simulate the model with random service time, and, as an improvement, we simulate again the model by substitute random service time with optimized service time. The simulation results show the different dynamic value of demand, reliability, average reliability, reliability cost and unreliability cost, where the results from the simulation with optimized service time are mostly better than the simulation with random service time. The total reliability cost of service does not all decrease, but the overall total reliability cost decreases, that is $ 3,409,315 became $ 313,595.

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Reliability maximization of a load‐sharing system without redundant components

Kim

Park

Hong

2022

Quality & Reliability Eng

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This paper considers a problem of determining the optimal number of components for maximizing reliability of a load‐sharing series system in which no redundant components exist. Previously, this problem has been studied numerically, under the assumption that the load–life relationship is described by a power function, and the component follows an exponential or a Weibull lifetime distribution. In this paper, our objective is to obtain analytical results for the optimal number of components given that a general link function explains a load–life relationship and the component follows a general lifetime distribution. We show that the optimal number of components non‐decreases with the elasticity of the link function and the ratio of the component failures sensitive to the changing design load. We also show that the premature failures occurring early in the life of a component affect the optimal solution, depending on whether a link function is used for scaling the nominal failure rate independently of the mission time, or it is used for scaling the nominal life dependently with the mission time. We believe that the result is useful in selecting the number of the components to use in a system when studying design trade‐offs at an early design stage.

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Derating design for optimizing reliability and cost with an application to liquid rocket engines

Cited by 12 publications

References 13 publications

An Overview of Bearing Candidates for the Next Generation of Reusable Liquid Rocket Turbopumps

An Overview of Bearing Candidates for the Next Generation of Reusable Liquid Rocket Turbopumps

Cost Optimization of Dynamic Service Reliability: A Case Study of Demand Fulfillment on Enterprise

Reliability maximization of a load‐sharing system without redundant components

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